Every old af member of the original death eaters remembers the day that the Dark Lord snapped and demanded to be called only by Voldemort… and that is thanks to Sirius black.
“Hey Tommy,”
“It’s Tom.”
“Okay yeah, Tommy…”
“It’s Tom.”
“Uh huh, that’s what I said…” Sirius was blatantly ignoring the absolutely pleading eyes of every other person in the room at that point, “so yeah, riddle me this Tommy boy…”
“I said it isn’t Tommy— ya know what?? Fine. Fuck it. It’s Voldemort. Just Voldemort. And guess what fuckers? It’s on now.” Tom riddle was gesturing around the table now, redness crawling up his neck with barely supressed rage, “hold on to your pure-blood panties, I’m about to go scorched earth.”
Collective groans were heard and suddenly the world went white for Sirius, as he personally found the answer to whatever riddle he was asking. Shortly after, he was deposited in the living room of the Potters.
As such, it should come as no surprise to anyone that roughly 20 years later, Harry Potter, godson of Sirius Black, endowed with all of the journals and missives of his well-missed godfather, could be heard at the final battle goading on the very same oldy Voldy with terms of endearment such as but not limited to:
Tommy
Thomas (pronounced with a French accent)
Tomtom
Tomahawk
Little Timmy boy
Tommy two cheeks
All of which inevitably served to create tiny little fractures in the snaky boy’s skull as he fought his own internal rage.
“It’s the DARK LORDDDD!”
“Oh but Tommy, may I call you that? Tommy? Well I’ll be doing that. You said your name was Tom. Why ever would I not comply with your orders??”