Rimuru Tempest/Chronology

Empowerment Arc
Satoru Mikami wakes up to find that he has reincarnated as a slime, which takes some getting used to. As slimes don't sleep, can't see and only have the sense of touch, he eats nearby grass to pass the time. After 90 days of boredom, the skill Great Sage finally finishes integrating the slime's desire to have a "conversation partner" which causes him to learn about the world with the new question and answers feature of the Skill. It turns out that the grass he ate out of boredom is actually Hipokte grass, a material for high-grade health restorative potions.

In the cave, he meets another lifeform, the Storm Dragon Veldora. The Storm Dragon proved friendly and teaches him how to perceive the surroundings via Magicules through the use of the Extra Skill Magic Sense. Veldora also reminisces about the peerless beauty of a Hero that defeated him 300 years ago... the two of them become friends and then name each other as equals. Veldora becomes Veldora Tempest, and the slime was named Rimuru Tempest. To break the unbreakable Infinite Prison, they agree to stake Veldora's freedom on Rimuru's Unique Skills, and Veldora gets stored in Predator's storage space, stuck in time and undergoing Great Sage's analysis.

With a new goal in mind and friend in heart, Rimuru eventually gets out of the cave. It was only after using the Great Sage's mapping function that he succeeded though. During the 30 days after meeting Veldora, Rimuru eats more grass and rocks, namely Hipokte Grass and Magic Ore, as well as other monsters that he fights and kills, and develops some personal fighting skills to defend himself, such as the Skill Water Blade.

Whilst exploring the forest outside the cave, Rimuru plays around with a sound-emitting skill acquired from predating a cave bat and achieves speech. He meets a group of Goblins and gets invited to their village. It turns out the Goblins are being threatened by a pack of Direwolves. After hearing the situation from the village chief and being promised eternal loyalty, the good-natured Rimuru helps them, defeats the wolf pack's leader, and acquires the rest of the pack as subordinates. He tells the goblins and wolves to get along with each other, and thus the new village is born under his rule.

In this world most monsters are nameless, with only high-level Majin being able to bestow names on others. When Rimuru realizes that there is no convenient way to get their attention beyond addressing them as "you," he names them all. Among them, the village chief is named Rigurd, the chief's son is named Rigur, the new wolf leader is named Ranga, and a natural bloke goblin is named Gobta, who later becomes a remarkable figure among Rimuru's top retainers. All the named monsters evolve, becoming stronger, but they no longer fit their clothes or their door frames, so Rimuru, along with Gobta, Rigur, Ranga, and a group of Hobgoblins and Tempest Wolves, go to the Dwarven Kingdom Dwargon to acquire clothes and a skilled house builder.

Rimuru, after some misunderstandings, helps out a masterful blacksmith, Kaijin to fill his quota on swords per the King's request. It turns out the Magic Ore Rimuru ate in the Cave of the Seal is a high-class smithing material. In return for helping him out, Kaijin promises to procure Rimuru a good blacksmith, and Rimuru offers to help Kaijin's friends, Garm, Dold, and Myrd, who are very skilled at their crafts but bad at business. However, a certain Minister Vesta ruins this, and Kaijin, after delivering his quota, is exiled from the country along with Rimuru and three dwarven brothers. The four dwarves, Rimuru, and the company then return to the village.

Upon returning, some other Goblins' villages join Rimuru's new village after hearing of his grandeur. Rimuru names and evolves them afterward. The dwarfs and hobgoblins immediately start working on building housing. As they are constructing the new town, Rimuru meets four adventurers who are surveying the land in front of Veldora's cave on the Free Guild Branch in the small country Blumund's behalf. The adventurers are a happy bunch. Rimuru discovers that one of them was an Otherworlder, originally from Japan, going by the name of Shizu.

After spending some time together and learning about each other, Shizu loses control of her Greater Flame Spirit Ifrit. Rimuru managed to beat and separate it from Shizu. Unfortunately, Shizu is now dying of old age without her elemental spirit. Her full name is Shizue Izawa. She explained her situation to Rimuru; She was summoned by Demon Lord Leon Cromwell and now she asks Rimuru to "remind the Demon Lord of her existence" and help her students, asking him to absorb her corpse because she does not want to be buried in this world.

After absorbing Shizue, Rimuru can now mimic a human form - a beautifully androgynous human. Other key abilities acquired from absorbing Shizu and Ifrit include Body Double, Fire Manipulation, and a new Unique skill Degenerate. Rimuru, later on, sends off the trio of adventurers with a parting gift, with them promising to send the news back to the guild that his village is friendly towards humans. Rimuru now has a new goal in mind besides freeing Veldora, saving Shizu's former students, and beating Demon Lord Leon Cromwell.

Forest Disturbance Arc
Getting used to his new abilities and having the Great Sage adjust and mix them using his new Unique Skill Degenerate, Rimuru receives an emergency Thought Communication message from Ranga he runs to the current location of Ranga, finding him, Rigur and Gobta in the middle of fighting, with the rest of the Goblin Riders knocked out via Magic. The culprits turn out 6 Ogres who accuse Rimuru of being an evil Majin who conspired with Orcs to attack the Ogres. After a battle and with the Ogre princesses persuasion, Rimuru finally manages to resolve the misunderstanding. Inviting the Ogres to a feast since there had been no causalities and hence no bad blood between them.

They started the feast where they discussed the situation alongside Rigurd, Regurd, Rugurd, Rogurd, Ririna, and Kaijin. The ogres (numbering 300) were attacked and defeated by around 10,000 Orcs. Kaijin speculated that they were being controlled by a Demon Lord behind the scenes due to the absurdly high number, and after Rimuru heard that the ogres were simply going to charge into their deaths, he asked if they were willing to become his subordinates (temporarily even, if they so wished). After a while of thinking, the 'young master' of the ogres agreed to a temporary contract and they were thus named Benimaru, Shuna, Kurobee, Hakurou, Souei, and Shion, making Rimuru enter his low-activity state.

After he awakened, he was surprised to see the B to A- Rank ogres all evolve into Rank A Kijin. Later on, they were all assigned with jobs: Kurobee as a blacksmith and craftsman, Shuna in weaving and cooking, Shion as a secretary, Souei in espionage, Hakurou as an instructor and Benimaru as the army commander.

Rimuru's village was visited by Lizardmen envoy led by Gabiru who proposed Rimuru's group should be working under them against the incoming orc's invasion. It turns into a duel between Gabiru and Gobta, which Gobta won, causing the Lizardmen to run away. While pondering what to do about the incoming invasion, Rimuru was visited by a Dryad named Treyni who asks for Rimuru's help in exterminating the Orc Lord. Shion accepts on Rimuru's behalf and they began their war preparation against the orcs.

Rimuru sent Soei to negotiate with the lizardman's tribe chief, while the rest were ordered to make weapons and armors for the upcoming battle. After a week of preparations, Rimuru sets off together with the kijins and the goblin riders to start a counter-attack. They met with a lizardman fighting with some orcs and saved her life, she explains that she is the chief's daughter and Gabiru's brother and that Gabiru had overthrown the chief and is battling against the orcs at the moment. Rimuru promised to save the lizardmen and sets off to finally deal with the orcs.

The Kijin showed off their newly acquired power and Ranga managed to evolve mid-battle into a Tempest Star Wolf. Before Rimuru can battle the orc lord, Gelmud shows up, trying to kill Gabiru so as he can become food for the Orc Lord, but after Rimuru prevents that, the Orc Lord Geld kills and devours Gelmud causing him to evolve into a demon lord seed and becomes an Orc Disaster.

Seeing as the kijin's attack isn't working against the orc disaster, Rimuru chose to battle it by himself. After a fierce battle of corrosion and devouring each other, Rimuru managed to beat down the orc disaster and convince him that Rimuru himself will shoulder the sins of the orcs, and let Geld rest in peace.

After the battle was over, Treyni announces a forest meeting to discuss the aftermath of the war and invite every participating races to bring over their representatives. During the meeting, Rimuru managed to convince the participating races to not only forgive the orcs but for them to work together from here on out. Everyone agreed with the idea and Rimuru became the chancellor of the newly founded Jura Forest Alliance.

Demon Lord Attack Arc
With the orcs and other races now working together, Rimuru's town became even bigger and started to gain the attention of the surrounding eyes, monsters, and humans alike.

Gazell Dwargo, the Dwarven King, is surprised at the reports of the monster town and wishes ascertain their nature, while four Demon Lords - Milim Nava, Frey, Karion, and Clayman - plan to send their subordinates to them to scout them out. On the other hand, a noble from the Kingdom of Falmuth sends out a scouting unit consisting mostly of prison inmates to investigate the Orc Army inside Jura Forest. The Frontier Expedition Force led by Youm was tasked with that job.

Demon Lord Awakening Arc
Rimuru was angered because The Kingdom of Falmuth killed many of the citizens of tempest, including Shion and Gobzo. He decides to absorb them but Eren intervenes telling Rimuru that he can revive them by massacring 10,000 humans, thereby becoming a demon lord. Great Sage deduced that the chance of success was 3.14%. Rimuru then makes his resolve and sets his plan in motion. Rimuru starts his attack by using a spell called meggido and mercilessly massacres the falmuth army. After about 5,000 or so have been slaughtered, he aquired a skill called merciless, which harvests the souls of those who have lost the will to fight. He then immediately uses the skill to kill the rest of the farmus army. The only survivors were the king of falmuth, archbishop rayhiem, and the court mage razen. All of this happens while confronting the three. After which, Rimuru begins his harvest festival, an event where one becomes a true demon lord and puts him into sleep. Rimuru begins the feel extremely tired, and there are still dangers around, with razen surviving his skill merciless. because of this, he summons ranga to take him back to town. he also summons 2 Greater demons and 1 archdemon to capture razen. immediately after, he loses conciousness, and begins his harvest festival. During which, his unique skills then evolve into ultimate skills. His unique skill great sage evolves into ultimate skill wisdom king raphael by sacrificing degenerate, and his unique skill gluttony evolves into gluttonous king beelzebub by sacrifing merciless. After which, he wakes up with raphael taking the reins of his body, who thens revives shion and the rest of the fallen citizens. He then falls back into sleep and wakes up three days later.