So I've always thought the Identity Crisis episode of Danny Phantom, with the two Dannys, was kind of silly (idk, feels like the concept should be treated with more gravity, like when Steven Universe gets his gem ripped out, you get it) but thinking about it in the context of a protective ghostly obsession, it's fascinating.
Like, Danny's "ghost half" takes the ghostly obsession with him, and it becomes everything to him. His purpose is to protect others, he doesn't exist for anything else. He succumbs to this unnatural drive, can't care about anything else. He's a ghost now, and ghosts need to feed into what they are to exist.
Meanwhile, "human" Danny has lost his purpose. The show has him goof off, which works, but I'm imagining him becoming increasingly lethargic, ironically dead-eyed, just kind of going through the motions. He doesn't want to fight ghosts, even if he could, but something is so clearly missing from his life.
Neither of them seem right. The ghost is becoming more and more otherworldly, out of touch, no one can bring themselves to meet his toxic geeen gaze. The human is apathetic, not even sad, just, not all there. Reckless with his relationships and his secrets, snarky in a way that's more hurtful than funny.
And then they come back together, and for the first time in days, he's Danny. He's got spark and life and empathy, and it doesn't hurt to look at him anymore, in either form. And that's how they realize that he can't just be one or the other, not anymore. He needs both sides of himself, maybe not to exist, but to be the person he is, and wants to be.