wierd thing came to me when i was seeing my tiers

[shady15]

Tier Z: Elite: Reserved for Xaero, Master of the Arena Eternal. what does that mean? when i press on the tiers it comes for me ?!

[Asuka_]

Actually it was a joke from the devs i think (read it somewhere).
Anyway, if you didn't play quake 3 it makes allusion to the final boss in the single player mode called Xaero (he's a model to choose also lol). As for the arena eternal thing, well you should read the quake 3 plot/story if you are interested to know about it.