He later claimed the person was a troll but still.

Aggressively tell people dealing with suicide to kill themselves, and he gave them instructions on how to do it. He's unable to handle criticism and lashes out as his own fans, even if something super minor.

He full on Neo Nazi and denies the Holocaust. Got banned from DW and the ZDoom forums for racism and sexism. He did not take inspiration he ported pictures of real dead bodies and put them in his mod. He used pictures of real dead bodies as sprites. This whole thing is made even more laughable when he wrote a manifesto decrying ID of copying his life works! (Despite the fact the elements he's talking about were in the cancelled Call of Doom rendition of DOOM 4 before his mod existed) Has stolen assets without asking for permission from other modders for his Brutal Doom Project. The other people are pretty questionable in themselves, but Marcos has, in no specific order (I won't link it cause I don't want to give it attention but just imagine a souless Doom clone not joking looks like he just painted over the ID assets with his own stuff). Long story short, along with some other people who have a bigoted history, the infamous Marcos Abenante was invited to the show, to display his newly announced game.

Brutal doom not working with gzdoom