He's always there, talking about your doubles, telling you heavy is coming, pulling you into a losing match just before he calls mercy on it. How's he find the time? Is the Crucible scheduled as such that there's only one going on at any time? Even then, he's always in the Tower waiting for you to walk by so he can yell across the hallway, "Hivebane-senpai, please notice me!".
Maybe he's watching Crucible matches inside his helmet. I wonder what other things I can watch secretly inside my helmet...
-
Space magic..... In all seriousness, I personally think that most of the stuff he says is prerecorded into the Crucible's announcement system. When an ordinary event happens, like ammo boxes spawning or a team taking/losing the lead, the system detects that and plays the associated message. Possibly, Shaxx has monitors over every arena, each of which he only glances at for a bit before moving to the next arena. However, when a Guardian in a match pulls off some impressive feat, Shaxx either notices that by himself or is notified through the system and starts ranting about how good that Guardian is.