Umumtu

Technically the villain, Umumtu is the primary antagonist of Season 1. She is the one pulling all the strings and levers, working agains the Heros and trying to achieve her goals in a very single-handed way.

What She Wants

Her entire goal is to first find Veza, second fix the world, and a distant third deal with whatever had to be done to get one and two done. It's as simple as that. Nothing in the whole of creation is as important as finding Veza, and fixing things with her. So what if they burn this world they made to the ground? They'll just make another one, and not mess it up this time.

In fact, if she admits it to herself, that's her plan B. If she can't fix the world, she'll end it. That'll fix everything; it has to, right? It's a reset to the begining.

The Plan

Humans are easily corrupted by magic. It is unfortunate, but true. They aren't the only race that can be corrupted that way; it simply takes longer with the others. But Humans in power will try to keep that power no matter what; that opens them up to corrupting influences. This can be exploited.

The reason that Humans are so easily corrupted is because they are incomplete. So are Kivuli. So, the corruption is simply the race looking for it's missing pieces, and filling them with magic until they burn out. Instead, if it's filled with the essence of a Kivuli, then it will be complete, and a new race will be born.

Immediate Steps

Cultivate Humans in positions of power who are also doing terrible things. Not only do they deserve whatever happens if things go badly, but they're the easiest to control. Offer them power and magic. Punch a whole through to the Living Realm, creating a pocket realm for the Kivuli, and letting the Human channel magic from them.

While most of the time this ends in disaster, someshow promise, and the two worlds do start to merge.

Intermediate Steps

Control the variables enough to learn why it works sometimes, and fails others. Push more. Try to figure out what makes this work, and then try to perfect the process.

Long Term Steps

She has no long term, other than achieve her goals. She's winging this whole thing, and isn't being very calculating about it.