"Wait a minute," Luke held up a hand, because it seemed like once Ben and Vestara got going they could argue all day, and something Vestara had said had caught his attention. "What do you mean, your tribe?"

A tribe meant more than one person. A tribe meant a whole group of Force users, probably Sith. And that didn't jive with what Luke knew about the Sith. Weren't there supposed to only be two at a time? And wouldn't the Jedi have noticed a growing group of Sith?