"Oooh I saw those Goku sprites on Spriters Resource recently! They probably based Goku off my sprites, as this game just popped up recently, and Mr. Man was uploaded 4 years ago."

Yep. that makes sense. I just wanted to verify that was the case and not that both sets were inspired by a 3rd party asset. ;)

"Are you tryin' to say that I copied and pasted my work? Because I am the original designer of these base sprites."

Nah! it was pretty clear from the differences this was never a copy and paste (either from your work or their work) Plus your stuff has always been your own. I have to double check everything though. If I actually thought this might turn out to be you deriving stuff from someone else and not the other way around, I would have put a licensing flag on this right away. I was pretty confident this wasn't the case though, so I never put I licensing flag on it at all.

"I don't know why this needs to be brought up. I see a lot of mobile games on the play store using my assets."

Only because the timeline was unclear to me on this one. I wasn't sure where the dragonball z discovery sprites came from or when (commerical game? fan game? fan game that ripped sprites from a commercial game?) Usually I can find out what order of operations happen with a fan game project, but I wasn't coming up with very good information on DBZ-discovery. I bring up everything that could be a problem, just to make sure it isn't one. :) 

Good news is both sets of assets are copyright sound! bad news is, their set of DBZ sprites is not trademark sound. Oh well. I hope they don't get in trouble for that. Looks like a passionate project.

Sorry if this came off as insulting. That was the opposite of my intent. I just had to verify the information from your side.