『Fafnir』

Fáfnir is a character that appears as the central antagonist during Book V of Fire Emblem Heroes. He is the king of Niðavellir and the older adoptive brother of Ótr and Reginn. He was once a kind man and a benevolent king but became power hungry and now wants to invade worlds. Since his new target is Askr, the homeland of Alfonse and Sharena the leading members of the Order of Heroes, he fights against the members of the Order, including his stepsister Reginn.

He wears a crown that enhances his strength and makes him almost invincible.