Spoiler: Elheil totally succeeds in breaking the seal, summoning the otherworldly beasts, opening up the dimensional rifts and the dimension hole, so on and so forth.
He then proceeds to basically just "peace out". He failed the put the otherworldly beast under his own control so he lost, he can't continue in his vaguely motivated plot to destroy the Magic Council, oh no. This leaves the Council to fight back the otherworldly beasts, safely containing the ancient evil within the Rift of Worlds, and then explore the dimension rifts and other universes beyond the dimension hole.
The end result of Elheil's actions is that the Magic Council - his supposed enemies - get to increase their own power to unimagined new heights, and look like great heroes while they do it. It couldn't have gone any better for them even if they'd planned it! ...unless they DID plan it.
Basically my theory is this - the Magic Council wanted the power of the ancient civilization, but they knew there was no way they would be allowed to take it. This power DESTROYED the ancient civilization... and the present civilization just finished up a massive war that destroyed even MORE of the world and sent the rest of humanity to live on floating islands because the monsters have made the surface barely inhabitable. Obviously, no one in their right mind would support the Council wanting to put the world at risk for the sake of getting some more power.
So instead, why not have some third party who is not officially affiliated with you be the one to do the deed, while at the same time claiming that he's doing it in order to kill you? You wait until after he's done it, then "defeat" him. You get to look like the hero, and reap the rewards of unlocking all the ancient power too!
Meanwhile, Elheil presumably changes his identity, probably uses some sort of magical plastic surgery, and goes about his normal life. And no one is the wiser about who was REALLY to blame.
- It's also worth mentioning that the "we hate the Magic Council and we're doing this so we can get the power to eliminate them" thing is only really said by Elheil's minions. When asked why he's doing all of this, Elheil himself says that it's all For Science!.
