Web Novel/Timeline

Rimuru (Minami Satoru) is the main protagonist of the series, he was a 37 year old bachelor who got stabbed after saving his friend's life and died. He then reincarnated into a slime and met with "Storm Dragon" Veldora, thus, started a new life in a unknown world. The legend of the strongest slime now begins!

Events and Incidents:

 * True Dragons coming into existence. Veldanava was the first born True Dragon, the second one was Ice Dragon Velzado, the third one was Scorch Dragon Velgrynd, and the last one was Storm Dragon Veldora.
 * Formation of the Sovereign Alliance of Nasca Namrium Ulmeria Empire, a.k.a the Eastern Empire.
 * Rudra Nam Ul Nasca's promise with Star King Dragon Veldanava.
 * Star King Dragon Veldanava married a human woman (Lucia) and had a child together. The child's name was Milim Nava.
 * Veldanava started the Dragon family first by creating the dragons and then making a rule for True Dragons that they cannot have children with humans because the child will take a large portion of the parent's power.
 * Veldanava passed away and reincarnated as his daughter's pet dragon.
 * Formation of the Dwarves' country - The Armanent Nation Dwargon - by its first king, Guran Dwargo (grandfather of Gazelle Dwargo).
 * Birth of the True Demon Lord, Guy Crimson who granted the wish of his powerless summoner and destroyed both the summoners' enemy nation, ano his summoners' country as payment.


 * Birth of the True Demon Lord Milim Nava. Around that time, her pet dragon was killed by some country. In anger, she destroyed that country and awakened as a True Demon Lord at the same time as Guy. Unconsciously, she fought with Guy.
 * Ramiris was able to stop Milim’s rampage. In doing so she absorbed the magic of demons and the powerful aura of dragons and awakened as a Demon Lord.
 * The fight between Guy and Milim resulted in a waste land to the south-west of the continent.
 * Guy, Milim and Ramiris got acquainted with each other and became the first generation Demon Lords.
 * Guy Crimson and Rudra started their game of forever war between demons and humans.
 * Rudra Nam Ul Nasca became Emperor of the Eastern Empire.
 * Rudra Nam Ul Nasca making those closest to him promise to kill him or find someone that could if he ever lost control of Justice King Michael, mainly because it sees everyone as evil.
 * Birth of the second generation Demon Lords, including Ruminas Valentine the Vampire Queen, Dino the Fallen Angel, and Dagrule the Giant, though none of them became True Demon Lords.


 * Event that occured once every 500 years - The war with the Angels.
 * Birth of Dagrule as a True Demon Lord after his rampage in the war.


 * Third generation Demon Lords were born, including Kazaream the Curse Lord (Magic King), Karion the Beast King, and Frey the Harpy Queen.


 * The Storm Dragon Veldora rampaged and destroyed Ruminas's vampire kingdom. A Hero appeared in the midst of it and repelled Veldora. Afterwards, the Hero befriended Ruminas.
 * Ruminas moved her vampire kingdom underground while establishing Holy Kingdom Ruberion on the surface for the refugees and people escaping from war. She was later worshipped as the "God" Ruminas by the Kingdom.
 * The Western Saints Church was established in worship of Ruminas. A Pope, who was a vampire subordinate of Ruminas, was installed.
 * The Hero defeated Veldora 300 years ago and used Endless Prison to seal him inside the cave.
 * Leon Cromwell and Chloe O'Bell were summoned to this world, Chloe was then summoned elsewhere soon after.
 * The Magic King (Curse Lord) Kazaream was defeated by Leon.
 * Leon Cromwell awoke as a Demon Lord as well as a True Hero.
 * Kazaream was secretly revived.
 * Clayman, the Marionette Master, became a Demon Lord to replace Kazaream.
 * The Ten Great Demon Lords was formed.
 * Leon summoned Shizue Izawa to this world and implanted the fire spirit Ifrit inside her to save her life and control her.
 * The Hero launched an attack on Leon, freeing Shizue in the process.
 * The Hero went into slumber underground beneath the Holy Kingdom Ruberion, watched over by Ruminas.
 * Kazaream summomed Yuuki Kagurazaka into this world. Yuuki enslaved Kazaream using his Unique Skill.
 * Hinata Sakaguchi was summoned into this world.
 * Yuuki and Hinata came under the guidance of Shizue. Hinata later left Shizue after learning everything from her.
 * Hinata joined the Western Saints Church and soon got promoted to Captain of the Holy Knights/Knights Templars.
 * Yuuki formed the Freedom Association and became its Guild Master.
 * The Cerberus underground organisation was formed with the collaboration between Yuuki and Damrada.
 * Leon got in contact with Yuuki and employed him for summoning Otherworlders in order to look for Chloe.
 * Chloe O'Bell was summoned by Yuuki from her first summoning to this world. 4 more Otherworlder children were also summoned around the same time as her.


 * The "Lake Shore Dyed in Scarlet" incident. A summoned demon consumed a princess and destroyed a small kingdom. The demon was then subjugated by the Eastern Empire.

Empowerment Arc

 * Minami Satoru's reincarnation into a slime, born in the Cave of the Seal.
 * Slime "Minami Satoru" met with Storm Dragon Veldora and they named each other Rimuru Tempest and Veldora Tempest respectively.


 * The disappearance of the Storm Dragon Veldora.


 * A village of Goblins was attacked by a pack of Fanged Wolves.


 * The village of Goblins meet Rimuru.


 * Rimuru saves the Goblins' village and gives names to both the Goblins and the Fang Wolves, thus, enabling them to go through evolution. Goblins evolved into Hobgoblins while Fang Wolves evolved into Storm Fanged Wolves.
 * Rimuru journeyed to the Dwarf Kingdom with the Hobgoblins and Storm Fanged Wolves in search of a architect.
 * Rimuru gets involved in an incident with the Dwarf offical Bester. The incidents ended with Rimuru and 4 Dwarves exiled from the Dwarf Kingdom.
 * Rimuru recruited 4 Dwarves - Kaijin, Garm , Mild and Doldo - to his cause to help build the Hobgoblins' village.
 * More Goblin villages joined Rimuru's village.
 * The start of the contruction of the Hobgoblins' village that would soon become the capital of Tempest in the near future.
 * B-rank adventurer party of Cabal, Ellen and Gido along with A-rank Shizue Izawa met with Rimuru Tempest while journeying inside the Great Jura Forest.
 * Otherworlder Shizue Izawa passes away and was then absorbed by Rimuru Tempest. Following this, Rimuru acquired a human form.
 * Cabal's party got acquainted with Rimuru's village, setting up the premise for humans interacting with Tempest in the near future.

Forest Disturbance Arc

 * The Orc Lord/King was born among the Orcs.
 * Orcs, led by the Orc Lord/King, rampaged throughout the Great Jura Forest, wiping out monsters along the way, one of the victims is the Ogres' village.
 * Rimuru met 6 Ogres, who were the last remaining survivors from the Ogres' village attacked by the Orcs, while they were on the run.
 * Rimuru recruited the Ogres to be his subordinates and named them accordingly: Benimaru, Shuna, Souei, Shion, Hakurou and Kurobee. The 6 Ogres then evolved into Onis.
 * Lizardmen sent out Gabil, the Lizardmen Head's son, to recruit war potential around the Great Jura Forest to counter the approaching Orc forces.
 * Rimuru has an audience with the Lizardmen led by Gabil. The negotiations for an alliance ended in failure due to Gabil's foolishness.
 * Rimuru sent Souei to form an alliance with the Lizardmen Chief.
 * Gabil's troop collected Goblin villages from the Great Jura Forest by force. He then led a coup to topple his father and claimed the position of Lizardmen Head and declared war against the Orcs.
 * Gabil led the forces of the Lizardmen and Goblins to engage the Orcs.
 * Rimuru and his forces set out as reinforments for the Lizardmen.
 * Rimuru's forces annihilated a portion of the Orcs Army with no casualties.
 * Rimuru engages in battle with the Orc Lord - Orc Disaster.
 * The meeting of 4 Demon Lords in viewing the Orc invasion to witness the birth of a new Demon Lord. The meeting was initiated by a Devil named Gelmudo.
 * The battle between Rimuru and the Orc Disaster was interrupted by Gelmudo. Gelmudo got beaten up by the Oni and then eaten by the Orc Disaster. As a result, Orc Disaster gained an ego and evolved into a Pseudo-Demon Lord.
 * Rimuru defeated the Orc Disaster singlehandledly, ending the Orcs' rampage.


 * Rimuru recruited the remaining Orcs into his forces.
 * The remaining Goblin villages joined Rimuru.
 * Formation of the Great Jura Forest Coalition.
 * Gabil got exiled from the Lizardmen and then joined Tempest along with 100 of his loyal followers. His sister and 4 other Lizardmen also joined Tempest under the guidance of Souei. The Lizardmen, after getting named by Rimuru, evolved into Dragonewts.
 * The founding of the Monster country Tempest: Rimuru's village developed further into a town/city thanks to the Orcs. Formation of the Tempest military: Hiryu, Shadow Squad, Green Numbers/Corps, Yellow Numbers/Corps.

Life in the Royal Capital Arc

 * The Dwarf King Gazelle Dwargo visited Rimuru's city and decided to recognize it as a country while promising future alliance and cooperation. The Dwarf Bester was brought to Tempest by Dwargo to work under Rimuru as a researcher.
 * Rimuru's city and the Great Jura Forest Coalition was established as a country and named Tempest.
 * Multiple Demon Lords' spies entered Tempest to investigate.
 * Milim befriended Rimuru and stayed in Tempest for several days.
 * Farmas Kingdom's Frontier Garrison encountered Tempest and decided to get aids from Tempest to strengthen their garrison.
 * Rimuru journeyed to the human countries, starting with Brumund Kingdom.
 * Milim Nava fell under Demon Lord Clayman's control and attacked Karion's country - Beast Kingdom Yuurazania. The attack resulted in both the castle Morotomo and the sacred mountain behind it to be destroyed due to Milim's destructive power.
 * Rimuru joined the Freedom Association.
 * Through the Freedom Association, Rimuru got acquainted with Garde Myourmiles, opening the trading routes and businesses between Tempest and various human countries.
 * Rimuru journeyed to Ingracia Kingdom to get to the Freedom Associations' headquarters and meet with Kagurazaka Yuuki.
 * Rimuru met the five summoned otherworlder children and became their teacher.
 * Rimuru and the children journeyed to Ulgrasia Republic to enter the Dwelling of the Spirits. There, Rimuru met and got acquainted with the Fairy Queen Ramiris. To compensate for destroying the Golem Guardian of the Dwelling, Rimuru created the demon Beretta to serve Ramiris.
 * Rimuru implanted spirits into the five children, saving them from dying due to the overflowing magical energy within their bodies. This included placing Chloe's time travelling spirit into her child form's body.
 * Rimuru bid farewell to the children after receiving news of Tempest coming under attack.

Birth of a Demon Lord Arc

 * Blood Shadows killed several citizens of Tempest including the Oni, Shion.
 * Rimuru battled Hinata Sakaguchi as she interrupted him on his way to Tempest. The battle ended with Rimuru safely retreating. Rimuru then arrived at Tempest only to discover the tragedy.


 * Farmas Kingdom's Subjugation/Invasion force marched towards Tempest with support from the Western Saints Church.


 * Rimuru completely massacred the Subjugation/Invasion Army of the Farmas Kingdom.


 * Rimuru summoned an Arch Demon and his two Greater Demon subordinates to chase down the survivors. The only survivor from the Subjugation/Invasion Army was the King of Farmas Kingdom.
 * Rimuru evolved and awakened into a True Demon Lord through using the 10,000 souls of the Subjugation/Invasion Army.


 * Harvest Festival of Tempest: Revival of the Tempest citizens killed by the Blood Shadows along with Shion, evolution of the Onis into Fair Onis and Dark/Evil Oni, Strengthening of every monster in Tempest under Rimuru's rule.
 * Formation of the Yomigaeri.
 * Rimuru named the Arch Demon he summoned Diablo - Diablo evolved into a Demon Noble/Demon Duke.
 * The reappearance of Storm Dragon Veldora: Veldora was released by Rimuru after unsealing the Endless Prison.
 * Conference between Tempest, the human countries and the Dwarf Kingdom: establishment of alliances and cooperation. Among the human countries, there's the Brumund Kingdom and the Sorcerer's Dynasty Sarion.
 * The Fairy Queen Ramiris intruded upon the Conference to warn Rimiru of Tempest's impending doom due to the Walpurgis Banquet of the Demon Lords.
 * The Walpurgis Banquet - the meeting of the Demon Lords with all Demon Lords attending it, including Rimuru Tempest.


 * At the meeting, Clayman's plan to destroy Tempest was exposed due to the collusion of Demon Lords Milim Nava, Frey and Karion. Rimuru then killed him.


 * Rimuru was accepted into the circle of Demon Lords and granted the domain of the entire Great Jura Forest.
 * Karion and Frey resigned from the seats of Demon Lords to become Milim's subordinates.
 * The Demon Lords decided on renaming the circle with Rimuru naming the current Demon Lords - Eight Star(Octogram) Demon Lords.

Saint Demon Confrontation Arc

 * Farmas Kingdom entered into a civil war due to failure in subjugating Tempest.
 * The Western Saints Church received words of the failure in subjugating Tempest and Rimuru's ascension.
 * Rimuru returned to Tempest and prepared for the invasion of the Western Saints Church.
 * The Western Saints Church dispatched 100 Holy Knights/Knights Templar under the command of Knight Captain Hinata Sakaguchi to subjugate Tempest.
 * Demon Lord Ruminas Valentine returned to her dwelling only to discover that her "precious" had been stolen. In rage, she awakened her Ultimate Skill.
 * Tempest battled the Holy Knights/Knights Templar. Tempest won the battle with zero casualties on both sides by neutralizing the Knights.
 * Rimuru defeated Hinata. They reconciled afterwards.
 * The Holy Knights/Knights Templar surrenderred and negotiated with Tempest in compensation and future relations.
 * Tempest was declared a country of Demi-Humans and accepted by the Church.

Founding of the Demon Capital Arc

 * Tempest sent out invitations to its allies regarding the Tempest Tournament.
 * Rimuru officially employed Garde Myourmiles as his minister and Department Head of the Departments of Business and Publicizing.
 * Construction of Tempest's Arena and preparation for the Tournament.
 * Rimuru employed Ramiris to construct the Underground Labyrinth as an attraction for Tempest.
 * Inhabitants of the Great Jura Forest paid their repects to their new ruler - Demon Lord Rimuru Tempest.
 * The Elves pleded with Rimuru to rescue their brethens that were captured and enslaved by the underworld organization Cerberus. Rimuru accepted the request and rescued all the demi-human slaves from Cerberus.
 * Rimuru met Damrada - an Executive of Cerberus.
 * Rimuru picked up and named some monsters for the Labyrinth. These monsters included Insect monsters Zegion and Apito, fox monster Kumara and 9 other beast monsters as well as 2 undead monsters Ghost King Adalman and Ghost Paladin Albert.
 * Ramiris' Labyrinth was completed with the collaboration of Rimuru, Veldora, Milim and Ramiris herself.
 * Invitees of the Tournament as well as visitors flocked to Tempest in large amounts for the Tournament.
 * Dagrule sent his three sons to Tempest to learn.
 * Tempest Tournament was held.
 * The Gozu and Mezu monster tribes' dispute was solved during the Tournament with the battle between their respective representatives Gozurl and Mezurl. After the Tournament, Rimuru employed them as boss monsters inside the Labyrinth.
 * Rimuru got acquainted with Sorcerer's Dynasty Sarion's Empress Elumeshia Elure Sarion during the Tournament through the introduction of Duke Elalude of Sarion, Ellen's father. With this meeting, they promised further alliance and cooperation in developing technology.
 * "Hero" Honjou Masayuki - another Otherworlder - joined the Tournament only to give up halfway. Afterwards, he was employed by Rimuru as an observer on developing and adjusting the Labyrinth as well as a mediator with the adventurers.


 * The Oni Benimaru became the champion of the tournament after winning the final round.
 * The Underground Labyrinth was officially opened, with its debut tested by a Labyrinth Exploration Party.
 * Momiji - the Tengu Elder's granddaughter - proposed to Benimaru after witnessing his valor in the Tournament.
 * The Dryads and Treants reunited with their Queen Ramiris and became her subordinates. An area was established for them and the Elves inside the Labyrinth - formation of the Underground Labyrinth City.
 * Tempest's reputation spead out all over the world after the Tournament and the opening of its Labyrinth.


 * Rimuru created avatars based on the Homunculus to enjoy the dungeon with Veldora, Ramiris and Milim.

Demon Lords’ Gambit Arc

 * Hinata resigned as the Captain of the Holy Knights/Knight Templars and cut all ties with the Holy Kingdom Ruberion.
 * Hinata decided to go to the Ingrasia Kingdom to rescue the 5 summoned children from Rimuru's story and as per request of her teacher Shizue.
 * Chloe O'Bell got erased from existence and the children's memories.
 * Yuuki ambushed Hinata with the Hero retrieved from Demon Lord Ruminas Valentine.
 * Hinata battled the Hero. The battle ended with Hinata being killed by the Hero. At the same time, Hinata awakened as a True Hero.
 * Fritz, who journeyed with Hinata, managed to escape with the children and Hinata's coprse from Yuuki's ambush. They then returned to the Western Saints Church.
 * While the Western Saints Church members moaned Hinata's death, Demon Lord Ruminas Valentine revealed herself as the ruler of the Holy Kingdom Ruberion as well as the God Ruminas - whom the Church worshipped.
 * The Hero visited the Church and revealed herself to be Chloe O'Bell from the future that merged with Hinata's soul.
 * Hinata's soul left Chloe O'Bell's body and completed the cycle of time travelling. (See the Diagram Below)
 * Ruminas used her Ultimate Skill to revive Hinata.
 * Chloe revealed the story of the alternate future of chaos spreading around the world due to Yuuki as well as her current condition under Yuuki's control. Afterwards, she left to return to Yuuki's side.
 * Yuuki escaped Ingracia Kingdom with his trusted followers, leaving behind the Freedom Association.
 * Hinata and the remaining children departed for Tempest to entrust their care to Rimuru.
 * Ruminas and Hinata arrived at Tempest to propose an alliance with Tempest to oppose Yuuki. Rimuru invited Fuze - Guild Master of the Brumund Freedom Association HQ - along to discuss the matter as Rimuru requested him to investigate Yuuki. An alliance of 3 Kingdoms - Tempest, Holy Kingdom Ruberion, and Brumund Kingdom - was formed.
 * The Alliance launched the Yuuki Subjugation Raid though it ended in failure due to Yuuki having already escaped.
 * The Freedom Association was dissolved and reformed into the Freedom Arbitration Committee with Hinata as the chairman.
 * Demon Lord Leon Cromwell invites Rimuru to his territory - the magic city El Dorado.
 * Leon and Rimuru discuss matters regarding Yuuki. They reach the conclusion of an alliance in the end.
 * Yuuki was discovered escaping to the Eastern Empire through climbing the mountain range looming over the Dwarf Kingdom.
 * Yuuki versus Leon Battle: Leon launches an attack on Yuuki by himself after discovering his location.
 * During the battle, Yuuki awakened his Ultimate Skill and revived the Chaos Dragon - Milim's pet - and then killed it again to absorb its energy to strengthen himself.
 * The battle ended with everyone of Yuuki's followers dead except Yuuki himself and Kagari - a body possessed by the former Demon Lord Kazaream while Leon's 4 followers remained alive with one of them - Black Knight Claude -  converting to Yuuki's side due to Yuuki's Skill and 1 dead. Unbeknownst to Yuuki, Claude had been released thanks to Chloe and became Leon's spy in observing Yuuki.
 * Yuuki and Kagari managed to escape along with Claude and Chloe.
 * The battle also left a crater in the mountain range where the fight took place while alerting the Dwarf Kingdom nearby at the same time.
 * Rimuru and Ruminas arrived as reinforcements with Rimuru's force fixing the aftermath of the battle while Ruminas revived the dead knight follower of Leon. Rimuru kept the soul of the Chaos Dragon for its revival.
 * Yuuki successfully escaped and arrived the Eastern Empire.

Empire’s Invasion Arc

 * Rimuru revived the Chaos Dragon as a small dragon and gave it back to Milim - the reunion of Milim and her pet dragon Gaia.
 * Technology cooperation between Tempest, Sarion, Ruberion and Dwargon began.
 * Railroads were established throughout the Great Jura Forest and connected Tempest with Dwargon.
 * Yuuki climbed ranks within the Eastern Empire and soon became the head of the Mixed Corps within the Empire.
 * Rimuru was invited to the conference to meet and negotiate with the Conference Coalition, a.k.a the Council, in response to the movement of the Eastern Empire. The negotiations initially broke down due to the Council's selfishness but Rimuru intimidated them and forced the negotiations in Tempest's favor in the end.
 * As a result of the negotiations, the Council's HQ and the Freedom Arbitration Commitee's HQ were relocated to Tempest.
 * Dino visited Tempest and requested to be employed. Rimuru employed him as Ramiris's assistant.
 * Reorganization of Tempest's military. Formation of the First Corps, Second Corps and Third Corps led by Gobuta/Ranga, Gerudo and Gabil respectively.
 * Birth of the Black Numbers/Corps by Diablo.
 * Tempest's First Corps engaged in battling the Eastern Empire's Armored Corps tanks.
 * Tempest's Third Corps engaged in battling the Eastern Empire's Armored Corps airships.
 * Labyrinth Monsters engaged in battling the Eastern Empire's Armored Corps Labyrinth Subjugation Force.
 * Tempest's Second Corps, Fourth Corps and Yomigaeri engaged in battling the Eastern Empire's Armored Corps Tempest Captial Subjugation Force.
 * First Invasion ended in defeat and those who wished to defected to Tempest.

Ryuma Clash Arc/Clash of Dragons and Demons Arc

 * Reward and Evolution to those of Tempest and Labyrinth.
 * A COUP D’ÉTAT IN THE IMPERIAL CAPITAL.
 * Guy and Velzard visit Tempest and Veldora immediately runs away from his sister.
 * Storm Dragon Veldora engages in battle with Scorching Dragon Velgrynd and the Eastern Empire - Veldora loses due to being shot by Kondou Tatsuya, and is sealed away by Magic Cancellers and controlled via Rudra's Ultimate Skill.
 * Rimuru Tempest and Wisdom Lord Raphael engage in battle with Scorching Dragon Velgrynd and Storm Dragon Veldora - who was under Rudra's control.
 * Rimuru calls for the Black Corps and Diablo.
 * Rimuru Tempest frees his friend Veldora.
 * Rimuru uses Veldora`s Power in the form of a sword.
 * Diablo orders Black Corps Demons to engage in battle and to sexude the perimeter of airships as well as selecting strong individuals and keeping track of any individual actions.
 * The Royal Knights engages in single combat with the Black Corps top brass.
 * Velgrynd is angry because she believes her brother was killed by Rimuru.
 * Emperor Rudra uses Armageddon.
 * Ultima eliminates Vega.
 * Yuuki steals the Ultimate Skill Armageddon.
 * Angra Mainyu, according to Yuuki’s wish, declared to play a game with Rimuru.
 * The Emperor Rudra's funeral was conducted.
 * Rimuru declared his reign of the Eastern Empire in the imperial capital.
 * Rimuru ordered Krishna to bring an army.
 * Rimuru planned to leave the rest to Krishna and had planned to destroy the Empire in retaliation to the attack on Tempest, but somehow or other, had instead taken control of it. The Empire’s ruling party was eliminated, and only the Nobles remained. Leaving them alone would destroy public order, and cause civil wars. Rimuru wanted to at least abide by Rudra’s wish for the citizens’ happiness. Not as a Demon Lord, but as an “Ex-” human.


 * Rimuru waited for Krishna to arrive, before returning to Tempest to prepare for the coming battle.

Tenma Great War Arc/Heaven and Demons Great War Arc

 * Benimaru decided to accompany Momiji to greet the Tengu’s elder.
 * Dino attempts to kill Ramiris only to find out that there are many hindrances to that plan.
 * Dino was annihilated or so it should have been but was able to escape.
 * Dino, realizing there was no way to win, understood that he was defeated by Zegion.
 * Inside a castle the Angels with pure white wings filled the hall. Among them were 10 individuals who stood out with 3 pairs of noticeably large, strong and pure-white wings, as well as 3 individuals with jet black wings, all kneeling in a row 13 Seraphim class individuals of the “Apostle of the End” group and Dino is one of them and two of them were pleading with surging emotions to retain their humanity. They were Kagali and Vega, who were resurrected as seraphim.
 * Tempest executors evolved and awakened into Demon Lords through using the souls of the Eastern Empire's Army creating a harvest festival for their subordinates.
 * Labyrinth executors evolved and awakened into Demon Lords and Ramiris's Harvest Festival of Evolution her strengthening of subordinates and form the executors subordinates.
 * A Walpurgis Banquet was called by Rimuru.

Guy POV
Meet Stellar Dragon King Veldanava and chose to challenge him without any hesitation. And ended up utterly defeated, Guy Cooperated with Veldanava, and become an “Arbitrator”.

How guy met Velzard she seemed to have found something interesting, and now followed alongside Guy. “Frost Dragon” Velzard.

Hero Rudra party challenge Guy and Rudra name “Demon Lord” Guy・Crimson! Shortly after Milim was born, Lucia and Veldanava perished in a magic attack caused by another country plotting against the Nasca Kingdom.

Milim grew up without knowing her parents’ faces. Also, not knowing of her relation to Rudra. Milim’s pet too, perished at the plot of a certain country. To calm down the vehemently enraged Milim, Guy had to take her on with everything he had. the repeated tribulations.
 * S/he is one of the first of the three Demon Lords. As the Arbitrator he/she convinced the both of them to read an agreement that each of the three would be different than the other two. One would pursue the ultimate power. One would live as one pleases. One would judge the world. Because their objectives were different, they could recognize each other.

After shaving off his Holy powers through countless rebirths, he lost his qualifications to be a “Hero”. Even so, Rudra remained a Saint, through sheer force of will. After a certain point, Rudra’s heart began to be tainted, as he began utilizing means that strayed from his past idealist self. Cold, cruel means. Attaining victory against Guy became the only goal.

Humanity's POV

 * Milim awakened as a demon lord at the same time as Guy but in different perspectives it was much later Milim awakened as a demon lord.