[Death by Mirrors]

Yep. Those avatars are taken directly from Trisphee's member list. They're all people who haven't been active for a while (to minimize the chance someone completely changes their avatar during the time they're shown on the first page). You need to find out who they are, and then "translate" their user number into the magic words.

The reward for solving puzzles is a hint so you don't need to fruitlessly search everywhere for the right person.