ideas for books

Little harry reads in a library book that demons make deals in exange for one's soul, so he decides to summon one and ask for it to be his friend

Now, as for which demon answers the summons, i imagine it could be meliodas(seven deadly sins), a servant(fate) such as medusa, or a devil(dxd), the summoned demon may be the original or maybe a reincarnator, i am leaning on a non-reincarnator female issei from dxd after all the canon stuff from an au timeline without the exe stuff. Detail: it WON'T be a mixed world! Harry's magic would have reached another universe, and now that issei has the spacial coordinates, she can come and go as she pleases

Issei would then sense harry's aptitude to magic and enter a standart devil-mage contract with him, in witch they pretty much become each others familiar and are required to help fighting each other's battles, issei then starts to teach harry human magic. That or she just reincarnates harry as her bishop, but since the imagination magic of devils is way too op i will most likely keep harry human

About the durslays, i will either have issei hypnotize them into ignoring harry(because harry doesen't want their love) but otherwise properly providing for him, or just taking harry to live with her in dxd

I may also have harry renamed by introducing himself as "freak" when he first summons issei and issei explaining that "freak" is an insult and not a name, she then gives harry a proper name (maybe ryu or something, i am not good with japanese names), that or using a magical ritual to dicern his name

I want wands to be sort of a permanent all porpouse magic circle, that can cast pretty much any magic at a severly reduced efficiency, the reason why wands are so mainstream is because standart human magic require a lot of math calculations for every single magic circle, and said circles are made to cast just a single spell and then disapear. Of course, harry having trained to use those calculations most of his life, he will prefer to use magic circles then wands, maybe he will even dismantle his wand to learn how it works and to improve his own magic circle formulas, he will just wave a normal stick arround so the hogwarts' students point less fingers at him whenever he casts magic, as the magic circles are already eye-catching enought

Issei will be joining hogwarts as harry's familiar