I wouldn't say I have any one rival, but:
If I am playing with any semblance of strategy, I generally like to target high-priority players on the enemy team. Pretty much this means if someone (who is infantry) I recognize is doing well on the scoreboard, I may go out of my way to kill them. 95% of the time, though, I just berserker charge into the frontlines.
Other times I might pick someone out of the crowd and target them specifically, generally if they seem to have a similar build as me... got to show the new guys (hah) who is top polepal around these parts.
Lastly, I might target any siege player (you know who you are) that I come across in battle since we're all best of buds and I like to kill my friends.
Okay, that last part might sound a little bad...
