Well, this is my first idea and I forgot about some things you guys said.
My idea was make a card that you need to feed it before use or it die, then I will change make it Immaterial for its owner ( you cant buff or fractal it, but the opponent still can target and kill with otys, eagle eyes... ) and since is not a pure darkness creature it dont be affected by Nightfall.
I just wanna make some different because 90% of the games I play oponent have Otys+firefly queen+fallen druid+quintessence