Miles's uncle, the one adult who tells him he is fine as he is, and a masked enforcer for the man tearing the city apart.
Aaron Davis is Miles’s uncle, who moonlights as a masked enforcer for Kingpin and keeps it from his family. Mahershala Ali voices him in both films.
He is the emotional engine of the first film, and the trick is that neither half of him is a lie. The uncle who takes Miles out at night and tells him to be himself is the same man in the mask, and Into the Spider-Verse refuses to let either version cancel the other.
Minor spoiler
In Across the Spider-Verse, the universe Miles ends up in is the one where he was never bitten, so nobody became Spider-Man, and Aaron never died. That is the version of Aaron Ali voices in the second film, and it is the worst news the film has.
Show detailsAnd the other Aaron Davis
Donald Glover appears in live action in Across the Spider-Verse as an alternate Aaron Davis, reprising the role he played in Spider-Man: Homecoming. Wikipedia records it as a reprise rather than a lookalike, which makes it one of the few times a performer has carried the same character between two of the continuities in this catalogue.