Razen/Chronology

Demon Lord Awakening Arc
Razen attacked the Jura Tempest Federation together with his nation, deeming its inhabitants a threat, but realized too late how powerful his enemies were. At first, he thought Hinata Sakaguchi had defeated Rimuru, Tempest's ruler, but is informed by Hakurou that he survived. He possessed Shogo Taguchi's body after saving him from Geld and thought that with his abilities, he could put a fight against a Demon Lord. Upon seeing Rimuru still alive and well, he realizes that Hakurou wasn't kidding. However, after surviving Rimuru's Megiddo attack thanks to his new Unique Skill Survivor and seeing the devastation of Falmuth's army, he realized he could never defeat Rimuru, so he tried to escape with King Farmus but was instead captured alive by Diablo.

The Octagram Soars Brightly Arc
Razen has fallen under the effect of Diablo's Unique Skill Tempter, which makes him unable to disobey Diablo's orders. He gets tasked with assisting Diablo and Youm with the scheme of taking over the Kingdom of Falmuth and effectively turning it into a puppet nation of Tempest.