Down Air

Down Air is Byleth's slowest aerial, coming out on frame 23. It boats the strongest knockback of any Dair spike in the game, alongside very high damage. It also has a lot of landing and ending lag though, meaning it is a high risk high reward move. It also boasts very high shield damage, meaning that combined with most other attacks, Dair will break a shield.

Dair can be comboed into through Up-b, but on most characters this can only be done on no DI or DI in. Dair can also be used to start combos with help of a platform: If you hit an opponent standing under a platform and land on top of said platform, at low % it can combo into utilt, ftilt, up-b, and nair. at mid %, it can combo to uair.

Finally, it can be used offstage to spike people with the tip of it, or the hilt of it can send people upwards. Versus an airborne opponent above the stage, the hilt will kill sooner then the spike. However, if they are offstage or grounded, the spike will kill before the hilt. This is due to the spike having higher knockback versus grounded opponents. It can also be used to twoframe, hitting very deep below ledge and lingering for 3 frames. This is a hard callout, but if you land it, it is almost always a guaranteed stock.