What if a God Eater have their control armlet destroyed and to save themselves from aragamification, they devoured their God Arc, resulting with them gaining an aragami arm and the ability to speak directly with the core of their former Arc (a personality with gender opposed to that of the God Eater is recommended) and somehow they end themselves at the world of Tokyo Ghoul were somehow they save a Ghoul child and adopt them. From that moment, the half-aragami ex-God Eater will try to adapt to a society where man-eating monsters are not mindless beasts, as well as the difficulties of being a night vigilante, searching for a way home and pondering about his/her points of view about ghouls and society, bringing inner conflicts and gaining eventually a neutral perspective but with the hope of both species' coexistence.
-The protagonist is a God Eater with a mutated arm, due to his/her Oracle cells been out of control, with their God Arc core being the only thing that is able to subdue it, so the core becomes a permanent mental companion with it being female if their Eater is a male and viceversa.
-Been a half aragami DOESN'T mean that they must consume human meat to eat. Their arms have the function of devouring in their pseudo-Arc forms but with battle purposes (ex. recharging their ammo, assimilating Rc cells properties and abilities). Obviously, their Oracle Cells requires sustent, so, in other words, they will have a bottomless appetite but they can consume normal food. It's convenient in that they can pass as normal humans (ghouls hate human food passionately, with the exception of coffee) and it could be used as a gag (you know, monetary problems due to a glutton and the likes)
-Oracle cells are highly adaptable and, in some cases, superior to Rc cells. Some of their characteristics are: being able to devoure any material at reach and learn its properties so they can copy them; they can only be destroyed permanently by something that contains Oracle and if a non-oracle attack somehow damages them, they can regenerate immediately; they can be used as material for a multitude of constructs due to their mimicking abilities and swarm organization; when injected into a compatible human (aka. God Eater) the host gains superhuman physical traits like augmented force and increased passive regeneration…
-A lot of powerful ghouls have a great control of their abilities and Rc cells, so the protagonist must learn to master their Oracle cells in order to have an extra edge in combat, apart from their pseudo-God Arc that comes with the arm. Creating weapons made of pure oracle or infusing items with it and replicate some Ghouls abilities are some of the possibilities. By the way, the aragami arm could be considered a kagune of some sort, so developing one seems redundant and God Eaters could surpass Aragami in terms of brute force, so imagine a God Eater with a aragamified limb...
-The child ghoul must be in their pre-teens or early teens and have an alternative source of food (coffee mixed with medical blood looks like a good idea). His/her presence in the protagonist life is a key factor to his/her developing opinion about ghouls.
For any doubt, search the wikis or ask by PM. I only know about Tokyo Ghoul by fics and its wiki, I've never read the manga either anime so I´m not an expert.
