Good Dumbledore , OP Voldemort but not too much that he is downright invincible gonna keep it as close to books or movies like when harry fights Voldemort , something's will change due to interference of oc , oc will explore the wizarding world during vacation and deal with Hogwarts and its problems during school year , it'll be mostly about how oc survives the war and tries to save his family and will do his best to take advantage of whatever he can to get stronger but it won't be straight up make him OP he will struggle very much (in this magic is not easy to learn even for an genius so he'll struggle to learn advanced spells he will only be good at spells which are in his year example-in first year he will learn 1th year spells but the second year spells will be hard and he will struggle to learn them ) , so he will be mostly all rounded like Jack of all trades but will have some type of magic at which he will be good . there will be deaths I tell you but in latter far off chapter after 1th school year ends in the holidays there will be a bunch of oc will be introduced. In second year harry and draco will join the school so there interaction will not be that much but will be enough to keep the oc in the story .