Continuation of me explaining my au idea of partially amnesiac Madara because I can't get it out of my head + doodles.
Like I said before, Madara is... lost. His memories are blurry and scattered, mostly due to one of his eye being already consumed by Amaterasu's hearth, but also because of the half baked resurrection jutsu.
It's a very odd process, possible mostly because of the seals left by Mito/Kurama on his body when Tobirama asked for help and the fact that it only needed something to 'stitch' back together the soul and the now functioning body (because Tobirama is a freak and accidentally just fixed the heart wound. It's a bit Frankenstein monster like except there are no one else's body part into play, just seals and chakra threads.
But as a result, Madara is in a constant state of confusion, almost like in a daze. I'll delve more into this later as well, but he can't bear the sight of his reflection.
Despite all of this, he remains a powerful individual who can and will attack back if threatened. It's less calculated than when he was properly alive, more instinctive, but I like giving more of a power gap between the founder's gen and the modern Naruto gen, so like, Hashirama is still the only one who can handle him alone, lol.
Talking about Hashirama, he quickly realises that Madara being there is his fault, so he takes the responsibility of anything he'd do. He refuses to say his name at first, it's Madara himself who reveals his identity very much later on, and only after that does Hashirama call him by his name, sometimes. He doesn't bother putting on a facade anymore (not that he can truly do much with how open Madara is with his affection now) and calls him 'my friend' and similar variants (pretty tame) or 'my love' and 'my heart' (which made Tsunade choke on air the first time she heard it).
He calls him the sun sometimes, and Madara flicks his forehead calling him an idiot. This is an instant Hashirama values because it's one of the closest reaction the Madara he knew would have. It's uncanny to see Madara so passive and calm, he feels like his eye lack a spark of life.
Some part of him feels guilt when he is with Madara and acting like it's normal, it feels like betrayal to the Madara he knew, but another part of him simply clutches onto the fact that, even though incomplete, this is still Madara, that he can fix things, and it would be cruel to leave him alone to suffer.
For the rest of the cast, at first, most don't think much of Madara at first. Naruto and Sakura are a bit scared of him at first, because they've seen first hand Madara's brutal efficiency as he killed bare hands the group of shinobi pursuing them (I should eventually explain the details of how exactly he was brought back and all, but this post will never end if I do this here, so later) Sasuke was there, but unconscious, and he doesn't completely believe his teammates rambling at this point (especially since Madara can't stop starring at him and petting gently his head, Sasuke doesn't understand, but the man is too gentle for him to believe he could kill someone)
Tsunade and Shizune are also some who have a bit of an opinion since they examined him. They are confused and don't know what to do, so Tsunade called her medical expert grandfather, and was surprised to see Madara perk up at the name.
He is taken in by the main Uchiha family household, Mikoto volunteered to take care of him, and most treat him mostly as an elderly war veteran eaten away by ptsd (which he technically is, but they don't know that, they only act like that because of how Madara behaves)
Fugaku is unsettled, Mikoto wants to help, Itachi is very cautious (because of how Madara looks at Sasuke) and Shisui swears he has seen his face somewhere. It's only much later that they find a picture with Madara holding Kagami that was taken during Konoha's early days.
Alright, I'm stopping here for now, but know that I'll be back with more.