No Silmarillion here, only Third Age stuff.
Legate and
Mith are both pretty close, but not quite dead centre (though the troll on the Rohan flag is so hilarious I have to give it full points for humour
). Now looking at it, the riddle might be a bit too blurry in that regard, but I'll let you guess a couple more times before I give hints. I think you can get it.