Leixein
Hope this only for a relaxing place not harem gathering spot, in the first place the world power level different to far. I like his personality in 'the change of a dragon' novel and hope he doesn't change to much.
When you say that Issei will be able to give his wives a dragon make-up do you mean that you will turn them into a true dragon like him? dragon-shaped and everything? or just a constitution? As a half-dragon or just manifesting dragon skills because of the unique constitution.
Leixein:Dragon overdrive is his dragon form and since he's not full dragon then he can't change into a dragon right away hence where the chant comes in. He will be able to use boosted gear later but not the scale mail because I set it that way. For Issei to be able to use chainmail then he needs Ddraig soul inside the boosted gear, and since Ddraig soul is not inside the boosted gear anymore he won't be able to use the scale mail any longer. That's my setting on the boosted gear idk if that's true in the original or not. He will able to use the BOOST function and all of his wives will also able to use it since they will become soulmate. And each of them will have the heart mark just like the one on Irene's chest atm albeit at a different spot. Kinda like Fairy tail guild mark if you know what I meant :D And I'm gonna make all of his wives constitution to that of a dragon, just like how Devils/fallen/angels able to reincarnate a person into their own kind. Issei will be able to do that too later on but only limited to the one who will become his mates because I don't really like a guy enter his team/faction HAHAHA. That's how I'm gonna make his wives OP. đ and the birth of the 5th faction will descent on the world đ Like I said he's gonna be true dragon king or even god later on.
I dont think darkness will do but how about the princess(i forgot her name i think its iris or something) i mean she is quite stong i think she is perfect as a tank or a knigth and if i recall i correctly she has like a holy sword well you can also have yunyun and wolbach as bishop.... Well you do have a queen which is LD and a knight which suites ScĂĄthach and then 2 jeans perfect as a rook so add iris as a knigh and yunyun and wolbach or maybe megurin as bishop if not pawn hehehe