This is just brainstorming for how to get Mireli from Point A (faux-grumpy warlock) to Point B (as-of-yet-undefined-adjective Death Knight). Feel free to toss in any ideas of your own. Like I said, this is just an idea.
(I'm watching stuff on planes, hence the name. ...What? I'm morose.)
Someone in chat yesterday, I don't remember who, suggested that Mireli get lured over to the dark side by some unscrupulous influence. Warlocks by and large aren't very nice, and Mireli's one of those people who craves new and exciting powers to use.
This idea revolves around her falling in with a bad seed (probably would involve making sure nobody ELSE gets the Garnet treatment) and... after that, I don't know. Maybe Cult of the Damned stuff, maybe garden-variety asshole-ry. Either way, Bad Influence leads to Plaguelands leads to Hi Welcome to the Afterlife, Here's a Sword, Go Squish Some People.
The problem is, Mireli's... not vicious by nature. She'll probably be one veeery broken DK. Like, losing what few social skills she has at this moment in time. (Tor becomes an asshole. Mireli becomes a shell.)