Added 7 minutes later
You can't bring Markel back to life, thanks to Zephyr, of course. But as for Agrail... well, he doesn't look like a demon at all. For quite a long time, I thought that Agrail was a former TE demon worshiper who later fell in love with Isabel, etc. This explains his small size compared to ordinary demons, and also explains the staff and the dinosaur he rides. And his transformation after the Ritual of True Nature also looks quite logical. But it seems that it has been said more than once that Agrail is indeed a demon.
2 Deinler
Why Rutger specifically? Is he somehow special?
Added 6 minutes later
And regarding Markel: Zephyr fought him again when he was trying to find and free his father. And Markel looked quite alive and just as charismatic.
Added 6 minutes later
I saw it in Agrail. And as for Tieru, you're wrong to suspect him of such inclinations. Even when he was a demon, he carried the succubus Biara with him. A demon is really a state of mind, not an external appearance. And seriously, why half? Because the first one didn't affect the Griffin's heart, and the second one starts with a punishing strike. On the other hand, demonic troops obey and have corresponding skills.