Bellatrix was the only person who ever called me Rod, everyone else addressed me by my given name or nicknames like Roddy (which she said sounded too childish) and Dolphus (which, she commented once, sounded oddly similar to "dolphin," and that was the funniest thing I'd ever heard, though mostly because she was the one who had said it).
According to her sisters, Trixie was the nickname Bellatrix had given herself as a child, apparently because it sounded like "tricky." I called her that because she'd told me too, but I thought Bella suited her much better. "Beautiful Bella," I'd called her exactly once, some time before our first break up, stupidly thinking that because she and I were a couple, I'd be permitted to call her something no one else was allowed to.
Her exact response to that had been "Don't ever fucking call me Bella!" Which is why I was so confused when, just before our fourth year started, she changed her mind and ordered everyone to call her that.
I began to think of Bellatrix as two separate people, Trixie being the mischevious but sweet girl I knew and loved and Bella being the malicious and Dark version of her who I had never seen before. Of course, that was pointless, it wasn't just her name she'd changed, she was almost a completely different person. I couldn't stand that and resolved to do two things: to find out what had happened to change her that way and to never lose her.