Guy Crimson/Chronology

The Octagram Soars Brightly Arc
Guy invited Leon Cromwell to his residence and upon his arrival, Guy welcomed him with a kiss. They moved to a terrace on the highest floor of the castle to have a discussion. Guy implored Leon to attend the upcoming Walpurgis Banquet and mentioned that it was Clayman who called the Walpurgis and Milim cosigned it. Both Guy and Leon thought that the reports on Carrion's death were false and Guy was unsure whether this was one of Milim's games or not. Leon asked Guy whether he thinks Clayman is controlling Milim but he says that he is too intelligent to read the behavior of a moron like Milim. Guy asks Leon whether he will be participating in the Walpurgis. After Leon's reply, Guy asks him again whether he'd like to sleep with him but he declines. Then they started discussing Lamrys' suggestion to include Rimuru in the banquet and Veldora's resurrection. Guy was shocked to hear that the "evil dragon" broke free, at this point Velzard joined the conversation and Leon explained what he heard about Veldora's resurrection. After Leon finished his explanation Guy became very happy and interested in Rimuru. The three of them speculated that Clayman's actions, Milim's behavior and Veldora breaking free might be connected. Guy changed the topic and asked Leon about his collaborator from the Eastern Empire and asked him to be careful. After Leon left Guy brooded over the upcoming Walpurgis and got excited.

During the Walpurgis, before the actual meeting started he was calmly sitting in his chair waiting for everyone to arrive. Rimuru tried analyzing him but Guy was hiding everything and made it seem like he was a weak, inexperienced kid. Magically strong but unable to control his aura.

After the meeting started and Rimuru and Clayman started arguing but Guy told Clayman to defeat Rimuru with his own powers if he thinks of himself as a demon lord and asked Rimuru if he declares himself a demon lord. Guy told him that if Rimuru wins against Clayman he will allow him to adopt the demon lord title. When Clayman asked Guy if its okay for Milim to fight for him, he allowed it.

When the fighting started, Guy isolated Clayman and Rimuru from the others with a barrier. Lamrys asked Guy to allow Beretta to join in but he declined it instantly. Guy doubted Beretta's loyalty to Lamrys and thought he was suspicious. In the end, Guy allowed Beretta to participate but made him refuse recognizing another master apart from Lamrys from now on. If Beretta were to weasel out of the question Guy would have destroyed him but to his surprise he accepted. Guy was confused by Beretta's behaviour and it reminded him of a demon he knew. He thought that it wouldn't be so strange if they are of the same lineage but this demon in Guy's mind rarely birthed other family members. Only few were aware of him at all. Guy asked Beretta about his lineage and figured out that he was right. After he finished his questioning he let Beretta go. Beretta told him that with "that lord" serving Rimuru he wouldn't have another chance to show his skills. Guy had a guess who this "lord" is. It was Noir, and old friend of Guy. He was incredibly happy while watching the battle in front of him even though he could already see the conclusion. He decided to remember Rimuru's name.

When Rimuru was about to kill Clayman, he put up a barrier he copied from Guy. Guy was bemused but unangered by it. Rimuru asked if anyone wants Clayman alive but Guy spoke for the whole council and said he can do what he wants. After Clayman's death, Guy congratulated Rimuru and declared him a demon lord.

After Frey and Carrion resigned they had to get a new name for themselves since they have been reduced to 8 members. Guy asked everyone to calm down and work on a new name together. He dumped the job of coming up with a new name on Rimuru. Rimuru objected at first but Guy's intimidation made him accept.

Hero Awakening Arc
Since Dagruel kicked Dino out of his residence. Guy pressured Dino into living in Tempest because he himself didn't want to deal with Dino.

During a meeting between Rimuru and Luminous its mentioned that demons under Guy's rule tried invading western countries multiple times.

Later, Guy sent Rain to Ruberios but Diablo met her and defeated her. After this, Guy appeared and started chatting with Diablo. He said that the Disintegration Diablo used to defeat Rain would even kill him, only if it hits. Guy asked Diablo why he waited so long to evolve but Diablo responded with a question of his own, he asked Guy whether he thought there were anyone stronger than them in the world. Guy said that other than True Dragons there is no one stronger than them. Diablo started praising Rimuru which made Guy annoyed and asked him to stop. Then Guy mentioned that even though Rimuru conquered the Western Nations, Guy's subordinates are wreaking havoc there. In his view, it was just a prank on the humans. Diablo's response made Guy annoyed. At this point, Guy got a message from Misery and asked Diablo when White got named. Diablo explained to him proudly that it was Rimuru who named her. Guy found the situation laughable since the balance of power he maintained for thousands of years was shattered to pieces. He decided to ask about the other two of the primordial trio. Guy was utterly astounded upon hearing that both Violet and Jaune were named by Rimuru. After further explanation from Diablo, Guy got even angrier and decided to pay a visit to Rimuru later.

Eve of War Arc
Following his brief reunion with Diablo, Guy proceeds to Ruberios with Rain in tow and appears in front of Yuuki and members of the Moderate Harlequin Alliance, who are in the midst of escaping. Misery shows up shortly after and pins down Footman. Guy has his eyes set solely on Yuuki and doesn't spare a single glance to his companions. Yuuki discerns their identity from information he received from Clayman and Kagali but doesn't despair at this impediment; in fact, he cheerfully throws an offer of teaming up at Guy, knowing full well it would fail, just to gauge his intentions. Amused, Guy rejects, stating that the boy is an enemy of Leon, and that he came with the express goal of stopping him from joining the Eastern Empire, not wanting Rudra's forces to grow any stronger. Seeing that talking will lead nowhere, Yuuki proceeds to attack. Guy smirks, asking if he thinks he'll win, Yuuki replies with confidence, saying he'll have to defeat him eventually so all he was doing was speeding up the schedule. Guy orders Misery to let go of Footman and promises to Yuuki that he'll let them go if he manages to defeat him, displaying arrogance befitting of his title of overlord. Yuuki launches a kick at Guy, bypassing his barrier, but is met with pain from the sheer natural hardness of Guy's body, of which his previous attack left barely a scratch on. All of Yuuki's following attacks fail as Guy counters each and every one of them, including his Anti-Skill, beating the former to a pulp. Laplace attempts to sacrifice himself to guarantee the survival of everyone else, but Yuuki manages to get back up. The boy questions why Guy hasn't killed them, as he's only inflicted attacks that left him on the brink of death, he wonders if he has some reason. Guy admits to it but refuses to tell him so Yuuki quickly switches tracks and strikes up a deal with him, he tries to sway Guy's mind about them escaping east by proposing that while they're in the Empire, they'll act as his pawns and destroy it from within. Guy considers this proposal to be very intriguing and decides to let them go, warning them that they won't be so lucky the next time they meet.

A day later, Guy visits Tempest and intrudes on Rimuru's meeting with Leon and Luminous to complain to him about taking in more Primordials and disrupting the balance of the world. Diablo tries to kick him out and have him visit another date, but in the end was allowed to attend the meeting.