What's weird about the Mage of Exodus theory is how they came about to it.

-Aika dies
-Magicsearch reveals the killer is from the Genesis Clan
-Genesis-Truth says the murderer's not there
-Oh, must be Exodus.

How did they conclude that the killer was from the Genesis Clan in the first place? That's one of the things I was annoyed about before when I mentioned "mechanics go unexplained".

Depending on the mechanism, you'd have to weigh up between whether the spell was initially wrong, or whether the Tree's guilt interpretation was wrong.

I also thought Aika was an Exodus mage for the reasons Ark mentioned.

As for the new guy, I'm sort of 50/50 on him actually having Mage-of-Exodus powers at the moment. Exodus also doesn't seemingly have to sacrifice anything to use his power.