I’m going to risk making a fool of myself and try to guess the ending of the second season. (If you have read the books and know the right answer, please keep quiet.)
I’m putting this in <spoiler> tags to avoid giving away plot elements already revealed. If you haven’t been watching the show this will not make much sense:
It is 100% certain that in the climax Kazumi will be forced to use the Hougu that Pheles gave her. She will do it to save Yuuji, even though this will destroy her by using up her Power of Existence. However the writers are not going to kill her off, so there has to be a brief poignant period as she fades out, during which she must somehow get a new supply of POE.
We know of two ways by which a human can get more POE. The writers are of course free to pull something else out of a hat, but let’s stick with what we know. The two ways are:
- Die, be duplicated as a Torch, and somehow get the Reiji Maigo inside you. This seems impractical.
- Become a Flame Haze.
So here’s a wild guess. At the last minute Hecate switches sides and makes Kazumi her Flame Haze. This makes sense because the only way Hecate is ever likely to overcome her existential angst is to start experiencing the intense, scary life of a human being. She can’t become human, but she can experience it indirectly through a Flame Haze. And of the humans she knows, Kazumi is the only plausible candidate.
Could Hecate control Kazumi and make her an evil Flame Haze? A cool idea, but it probably wouldn’t work. Everything we know indicates that the contract must be voluntary for both parties. Also Crimson Lords don’t seem to be able to control their Flame Hazes; all they can do is offer advice and possibly withhold benefits (such as hangover cures.)
Also the Tomogara hate Flame Hazes and would try to kill Kazumi on sight. So Hecate would have no choice but to switch sides and fight her former comrades. This probably wouldn’t bother her; there is no evidence that she likes them.
UPDATE: Well, that’ll teach me!