"Vampire King Atlas. I'm sure you have a misunderstanding. The Undead Region and the Death Domain had no problem with each other in the last. Elisia would probably not do anything against you people. We all know that you have been neutral in the wars of the past. Why would we do anything to push you closer to them?" Asmadeus asked the Vampire King, failing to understand his reasoning.
He knew that Elisia was our to screw him over, but even she wouldn't be so stupid as to kill a Vampire General, knowing what consequences it might have. He knew why she wanted to kill Ryder. It was to bring trouble to him, but for that, she wouldn't mess with the Undead Region.
She had the levy to mess with the Demon Realm since the Death Domain and the Demon Realm both had almost similar strength, and both didn't have their kings. They could protect themselves from Demon Realm's assault.