Blárwolf (ブラーウルフ, Burāurufu) is a Blue Magic tome and a weapon skill introduced in Fire Emblem Heroes. It is effective against Cavalry units. It can also be forged into Keen Blárwolf, which can then be refined further.
Weapon Stats
Etymology
Blár is an Old Norse word for "blue", the color of the tome.
Gallery
Ursula casting Blárwolf.