My nickname was chosen based on 2 things. The word Invictus, for those who don't know, means unconquered or invincible in latin. My favorite poem of all time is Invictus by W.E. Henley. I was FUMING to the point of literally seeing red, punching walls, and almost in tears when Timothy McVeigh used this poem as his final words. I'm glad that mother****er is dead, because if he wasn't, I'd kill him. But, I decided in the end NOT to let him destroy the best poem ever written. I kept this nickname just to spite him, as he used the poem just to spite the law.
Anyway, the poem Invictus literally saved me from, well... doing something very dumb when I was younger. I've been using this nickname for almost 10 years now.
Secondly, I have a lot of Scottish blood. On my dad's side, I am a descendant of clan Armstrong. Their clan motto is "Invictus Maneo" - I remain unconquered. So, you could say Invictus is in my blood.