When activated, Byleth will pull out Aymr, and charge up a powerful downward swing. Byleth has 30% damage-based armor on frames 34-63 if grounded; after the startup animation, but before the swing itself. It is possible to gain the armor if Byleth lands before frame 34 as well. It can be reversed once and dropped through platforms as a deadly mixup option. It can also hit characters standing on the lower platforms of Battlefield. Aymr does incredible damage and knockback, on top of being able to break shields in a single hit. If used at the edge of a platform, Aymr doesn't impact the ground, but the hitbox will occur slightly lower (around where a stage's ledge is located). With appropriate timing and spacing, this distinction allows Aymr to potentially foil certain recovery efforts. Like other "bold" moves, the clean hit triggers Special Zoom.
Byleth may occasionally yell "Aymr!" while using this move. Similar to Peach Bomber from Brawl onwards and Ness' PK Starstorm as of Smash 4, the clean hit often causes Byleth to say only "Ay-" during the swing and "-mr!" at the landing.
Moves that utilize Aymr
Aymr is one of Byleth's four weapons utilized throughout his moveset, specifically bound to down moves. Aymr boasts incredibly high damage and knockback on all moves that feature it, though at the cost of extreme lag. Similar to Chrom and Ike, the moves use their own unique "heavy weapon" sound effect.
For his down smash, Byleth sweeps Aymr from front to back. Byleth's down smash is strongest in the game, in terms of damage, dealing a solid 23% on both hits. Both hits are equally powerful, and it also has the power to nearly break full shields with just one swing. However, it is also slower when compared to other down smashes and is punishable.
For his down aerial, Byleth swings Aymr downward, with the ability to meteor smash opponents. It is the strongest meteor smash from a down aerial move in Ultimate, being able to meteor smash grounded opponents at 85%, surpassing Ganondorf's down aerial in terms of knockback. However, it is once again extremely slow, with slow startup, ending lag, and high landing lag.
This axe is the personal weapon of Edelgard von Hresvelg in Three Houses. While it is in her possession, it grants her the Raging Storm combat art, which is effective against dragon enemies and lets her move again when the attack connects. Aymr can be wielded by other characters, but it will not grant Raging Storm to those without the Crest of Seiros and those without a Crest will take damage after attacking with it. The animation itself is based on Flickering Flower, a combat art learned exclusively by Edelgard once mastering the Emperor class in Three Houses, in which she holds an axe back and does an arching attack. Despite being linked to the Crest of Seiros, the Crest Stone embedded in Aymr is engraved with the Crest of the Beast.