People say Antifa, LARP, Q. Who knows.
A family member of mine who was at the speech later told me she was standing right next to Viking guy while Trump was speaking.
FWIW, she said he sounded even more odd than he looked. He didn't seem like a normal Trump supporter, just screaming things use obscenities over Trump speaking.
Make whatever you want out of that.
I personally talked to him at an AZ rally and he told me about his banned youtube. He is also on rumble though: https://rumble.com/user/YellowstoneWolfAZ?date=this-month