Looking for a certain dagger

Hey all!

I'm looking for a particular dagger, but unfortunately I can't find any information on it other than a single mention of the name on the wiki in a list of daggers. The dagger is called Charon's Left Arm?

It doesn't have a wiki page, but it has an entry in the list of daggers and I've found posts of people selling it and discussing it, but none mention where I would get it.

Where do I get this thing?

 

It's a level 21 dagger with no specific drop location or anything so u can get it dropped by random level 16-26 mobs or in chests that are in locations of that level range

 

Thanks so much!

Well. Time for more grinding then xD