A Secret Identity as a Second Personality

My ability is possession, which you could think of as a second personality. The more pain I feel, the more I can gradually take over. Once I have accumulated enough, I can replace the host. To have a body and existence of my own, I keep searching. After giving up on my original hosts, Q and the Heavenly Restriction, this time I've set my sights on three people: The Curse User, the Red King, and Zenitsu Agatsuma [I'm your substitute] [I will bear all your pain and take care of every problem] [In return... give me everything you have] Geto Suguru remembers how, during the hottest, most stifling part of summer, "he" appeared like a storm. He watched that person take over his body, steal his best friend, and destroy his righteous beliefs... At the time, he wanted to tell the whole world that "he" wasn't him. But years later, when he saw "him" again, Geto Suguru gripped his hand tightly and told him: [I'm yours] [Don't let go] Zenitsu Agatsuma remembers how, in countless moments of mortal danger, "he" appeared like a savior. He watched that person use his body to save a beauty, rescue his companions, and defeat his enemies... At the time, he wanted to tell the whole world how cool he was (in his main account), sob! Years later, when he saw "him" again, Zenitsu Agatsuma clung to his leg, wiping snot and tears all over him as he shouted: [Main account, my main account, come back already!] [My login password will always be 520!!!!] Me: "..." Me: "...I've told you a million times, that's just you! Could you please shut up!" Suo Mikoto remembers that the existence of his "second personality" helped him through the hardest times. When he saw "him" again, the Red King had switched to a new lollipop. His vivid, fiery red hair was swept to one side as he said, "If you want it, just say so. If you have nowhere to go, Homra is your home." I'm grateful to him, because he is one of my worlds. And this world is my home. ---Before You Read--- 1. This is probably a slice-of-life story with everyone doting on the protagonist (?). The main plot follows the male lead's journey from inhuman to human (? ) 2. The main story is in third person. I just haven't figured out a title for this blurb yet! 3. It will probably be a crossover mainly featuring Jujutsu Kaisen, Bungo Stray Dogs, To Your Eternity, K, and Katekyo Hitman Reborn!, as well as Demon Slayer, Yona of the Dawn, and others (?). It's fine if you haven't read them. The worldbuilding is barely involved, and I'll make everything up as I go. 4. Possession hosts: Zeno, Zenitsu, Muzan, Mikoto, Reborn, Toji, Geto Suguru, Q... Theme: Finding oneself