I’ve had a couple of opportunities to have reasonably civil conversations with Elothiomel, so I’ll chip in what I know that hasn’t already been mentioned here. Sorry if some of the is common knowledge, you never know what might help in resolving a Collector.
-He calls himself Elothiomel the Grasping
-He claims to be a collector rather than a Collector, but that’s pretty clearly a lie.
-He has people who collect things for him, either by soliciting donations or flat out stealing them and leave them in boxes scattered around the Forest.
-He is mad that we stole “his” boxes. Even though most of them aren’t labeled, many of them contain stolen property and some of that property was stolen from us. He seems to be particularly mad at Elias. As far as I know Elias is the only one he’s caught in the act.
-He does help out some people, but it seems to be more about recruiting for his weird cult than charity. I got a bad feeling from his charity collectors. They seemed kind and genuinely trying to help, but there was something not-right about them.
-His symbol is a hand with the fingers pointing down. Some of his boxes and followers are marked with it.
-He only personally seems interested in stealing extremely rare or powerful things. His followers are less discerning.
-He was able to disrupt my Crafting of Memory and contact me directly. I’d love to know how he did that.
-He has a fancy key. I’ve heard its an artifact that can open any lock, but I’m not sure how reliable that information is.
-He also created some sort of magical dye trap. It got blue all over Elias, but didn’t seem to have any actual mechanism.
-He murdered Aktosh. He’s ok now thanks to Miraculous Cures.