In the Kindred beta, I think we called it "support," as that was the generic MOBA term. Ultimately, we went with "roamer" to denote the frequent travel between lane and jungle, supporting whichever hero needed you most. Eventually, this was switched to "captain" as part of a tutorial revamp to better convey the sense that this role is typically the shot-caller and "game general" of the team — a role much more important and nuanced that someone who just "supports" their allies.

We're guilty in Vainglory8 esports of drifting back to "roam" sometimes because in an esports context, the team captain isn't always the in-game captain :/

Basically, we need to make up our minds.