Blade

Blade
Blade is the main antagonist of the original Brown Haze series. He has been trapped now, and since the series is moving to the next arc, he will not be showing up anymore. He has been trapped in Axel's crawlspace in his house and since he is moving, Blade will be stuck there until someone finds the symbols or either Robert or Austin draw the symbols and put them somewhere.

Axel
Axel was his main fixation until season 2 ended. Axel is the most interesting to him because he is related to it somehow.

Robert
Robert was brought into the whole thing by Axel and only really encountered Blade once before. He hasn't shown up any other time after that but he may show up soon.

Austin
Austin hasn't seen Blade yet, but was going to encounter him before some episodes he wrote were scrapped. Blade is still interested, even though he is trapped. Who knows what will happen next.