Information about or a stat block for Evard is very hard to find. I’ve been searching, because he of “black tentacles” fame is mentioned in Planescape. I looked through a bunch of old D&D materials, and didn’t come up with a lot. Mostly, I get that he’s a foe of Mordenkainen’s Circle of Eight in old Greyhawk magazines on DMs Guild. In particular, you can get a lot of information on I fed the description of him that I found into Dall-e and got the image to the left.
I gave Evard a touched-up spell set and some magic items. One of the sources that I found said that he authored a book on ghosts, so I may take a second pass at stat block in the future and give him some conjuration abilities.
Evard Stat Block and Token
I hope this Evard stat block is useful! If you’re looking for stat blocks for Mordenkainen, Bigby, and a few other notables, you can find them here.