The reason I am not doing a combination of both demon and devil is because I feel that it will make the reader op.
Now I have nothing against op readers but to me it breaks the flow of the story a little bit. Having a strong but beatable reader will help add drama and would make more sense.
Also I have one very important question to ask you all.
You have a choice. Would want me to:
1) add Rias and the others back into the fold as a extended harem?
Or
2) resolve the conflict between y/n and Rias but I will remove Rias and the others permanently. There maybe a little reference to them every now and then, but other than that they will be gone forever.
Choose wisely for the next chapter I post will be decide the fate of Rias and the others.