A Person that has anger issues, trusts nobody except for a few loved ones, they do not show their true emotions very well, the only time they express happiness or sadness is when something tragic or Joyful happens. They cannot help themselves but to be angry, they're angry at how society is and wish for a better change in secret.
Guy #1: " Hey..is he Okay?"
Guy #2: " Ignore him, Phil. He's a Karkat..I've seen one of those in California "
A sly motherfucker who uses their tactical tripwire mines to destroy your fucking ankles. You'll often see Kapkans waiting for you in a corner to break down a window or spawn-peeking to get that sweet satisfaction.
To accuse someone of some form of "ism" (sexism, racism etc.) and to proclaim that their denial, or any attempt they make to defend themselves, is proof that they are guilty. A favorite tactic of the social justicewarrior.