Casual11
I got an idea What if you make Trihexa 666 his child that born when he was fighting a powerful goddess in his mid journey by getting his and her blood and magic mixing when they where fighting and they stop because Trihexa was created and you can make it like Trihexa was normal until when the bible god seal the mc and Trihexa thought that his/her dad is killed so he/she goes berserk and turn as he/she look in the manga and get sealed to by the bible god but the seal is weak because he just fight the mc, so after the holy war that happens and him killing Lucifer and red and white dragon his power because weak and so is the seal on Trihexa and he/she break out of the seal and the only thing the god of bible can do is using his life as source to make new powerful seal (Sorry for my English, and if you don't like the idea you can just throw it out of your mind)