User blog:Isaac Kifer/Soul Sharing explained

Thoughout his adventures, Isaac has made a family with an assortment of mamonos and has so far avoided becoming an Incubus by sharing his soul with the mamonos in his family. This technique was created by both Isaac and Lic-chan when Isaac's fear of becoming an Incubus was brought up to her. The process entails stopping the natural production of his mana and the mamono's DE for a small portion of their souls to be swapped. This allows the natural abilities of the mamono to be utilized by Isaac and the abilities of the previous mamono, Hell-chan for example, allows Isaac to cover his hands and feet in flames and deliver devastating blows with her raw power. Lic-chan's soul however allows Isaac and other mamonos such as Hell-chan to use magic and this rule applies to all of the mamonos Isaac has shared his soul with. This process has a few draw backs however, the first being that although Isaac can now produce DE naturally like a mamono, his mana production becomes less with each time his soul gets shared. All the powers he can use require DE to use and despite being able to make it, more DE is required to use them then he can make and he doesn't have an unlimited supply. With each sharing of his soul, Isaac becomes more and more like a mamono each time and is more prone to primal desires and rage, getting closer and closer to losing himself entirely. The last draw back is that at the end, when his dream has been accomplished and he's made a family of every mamono on his ranch giving them each a proper home with the love, care and family that he believes they need; he'll finally give in to the DE that has accumulated in his soul and he'll have one last day to be himself before succumbing to Incubization. During that time, it's unknown what he'll do spending his last moments as himself before he becomes an Incubus and desires nothing other then to pleasure himself with his wives. There are only a few who know this however, those being himself, Lic-chan and Angie. Unbeknownst to Isaac, Lic-chan is trying to figure out a way for Isaac to avoid this fate.

"The day that I become an Incubus could be far away or it could be tomorrow, either way, when that time comes I'll have known that I've lived to my life. The thought scares me even still, knowing that I'll have lost myself after such hard work but as long as my family is happy, I couldn't care less. For those who knew me, I'm sorry that the friend you remember is no longer, but in you he'll live on. My only regret is that I could not have kept myself around longer to see what the future brings for my family and the 'me' that will remain after I'm gone."

-Isaac Kifer.