Padfoot was born with the name Sirius Black, but he mostly ignores that. He's seventeen, owns a motorcycle, wants to live as far from London as possible, which means anywhere in Scotland is good, and would be writing this bio-thingie in first person, except that Remus would probably kill him for unprofessionalism if he did.
Remus Lupin is the unwilling victim of, among other things, keeping a joint journal with Sirius. He would rather be reading right now, or perhaps getting a head start on his N.E.W.T. studying, but Padfoot has bribed him into writing this by giving him Chocolate Frogs.