Senpai:
In informal use, senpai (also styled as sempai) can refer to anyone whose attention you want to get—that could be someone you admire and want to be friends with or someone you're interested in romantically. Senpai made its first appearance in Urban Dictionary back in 2004, when a user defined it as "an upperclassman."
But I think Masq meant it in the 'kill, torture, destroy' sense. Or maybe not - now that I look at it again it might mean as above here.