just got the idea from a movie. so it would start somewhere in the future where the main character is like" ill sign the contract. I will do anything to get them back." and then it will go back in the past where all of this started. I don't really care how it happened like if he had a ancestor with a rare bloodline like a hellfire blood demon or something like he had to watch bad people do stuff to little sister and mom with him being forced to watch as there eyes gloss over from the pain and despair with there cheeks still wet from tears until they die from it. ( don't get pissed off at me because this is only a idea to start off with and I don't really care if you use it or not.) long story short. family dies, he is tortured and killed, deal with god/death/devil to give his little sister and mom a second chance with that days memory removed and a little explanation, somehow gets to space to find a massive organization that his dad worked in before he died with something related to his bloodline and or heaven and hell and how through a series of events his dad managed to get there. in exchange he is made into a demon that can basically sense what bad things a person has and will do. ( kinda ghost rider but no bike,). his real main goal is to track down eight escapees from the deep pits of hell which are the seven sins and the cardinal sin which is like the boss. oh, lets say that he managed to get the souls of his sister and mom and reincarnates them as some type of demons like for his little sister she gets... I don't really know what. and then his mom gets reincarnated as a succubus.