Ironically my most dominant unit in either of my playthroughs was my Warrior Anna paired with Tiki. Granted, Tiki will make any unit good (I gave Tiki to Jean in my second playthrough and he was almost as dominant) but I don’t think she really needed Tiki, she would have dominated anyway. Legions of nobles and trained soldiers, outperformed by a child. Lyn was another emblem who made both the units I gave her to into monsters: Ivy with her unique class in playthrough 1 and Bow Knight Etie in playthrough 2. Diamant in his unique class was also really good, with either Ike or Roy.