Yet Another Kingmaker
He wears a weird helmet. It's a fashion statement.
A man met on the side of the road. He killed a gaggle of highwaymen planning to ambush the party before walking back into the woods. He left a single white rose petal on the body of one of the fallen ambushers.
The party immediately attacked the man, but relented after finding that his motivations were not clear.
Strongly suspected as the Stag Lord.