(1) Remus Lupin
He is, I'd argue, the most useful father figure Harry ever gets. Dumbledore's too distant, Sirius too reckless (and thinks he's James) and Hagrid too bumbling. He protects and helps him but isn't afraid to tell him when he's been an idiot either. He's also, arguably, the most likeable and respectable of the adult cast despite his debilitating disease, and he completely bosses book three. Very underrated.
I like Luna too, but not as much as most people, I think. Wish she'd befriended the trio in first or second year.
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Who knew the Rivalry Rumble would be so predictable? SuperNiceDog, that's who.