no offense, but everyone above is right.
Ecole has no right to interfere with you considering you are doing this for FREE. As they said, if that was the case, then a shit-ton of chars, stages and whatnot would have been taken down and Mugen as a whole would have been deemed ILLEGAL and Elecbyte would suffer as well.
Truth be told I see this as some internet troll just doing something stupid to down your spirits and piss you off for his/her enjoyment.
Same was said for Garrys Mod when the Skyrim SNPCs were taken down via DMCA. It was not Bethseda that threw out this, it was just some 12 year old girl that did it because it made her feel special. If Bethseda wanted to take down the rest of Gmod's creations that Bethseda made even when said mods were made for NON-PROFIT, then a Whole other shit-ton of mods would have been removed, forgotten and thrown into the wind. Same Scenario, different reasoning.
Don't let this damper your spirits Sennou. Stay strong and fighting.

the number of chars Ecole created for Mugen have already been removed from the internet