I'm looking for a word that describes a person who desperately wants to make things right.
Like a person who would go to their physical and mental limits and even beyond, just to make sure everything's okay. A person who is so devoted (or maybe obsessed is a better word) that it is obviously dangerous, but they're too self-unaware to notice.
I'm not asking for a word for someone who's dependent, however. They would be just fine on their own, but when there's a problem, they'd do ANYTHING to make things right.
An example sentence could be "He's such a ___. He'll probably get killed trying to save everyone."