Does 'unspoken' fit the following sentence?
He stared up at the gang's unspoken leader.
It's never been declared that the bully the sentence refers to is actually the head of said gang, but everyone makes that assumption based on how assertive he is.
Would 'inferential leader' make more or less sense? I don't particularly fancy 'undeclared', which sounds like something you'd be more likely to use when going through customs. Any suggestions for alternative adjectives would be welcomed.