Pyra swings her sword beneath her. This is commonly considered one of her best moves, boasting a large, lingering hitbox, good shield safety, low profiling landing animation, great edgeguarding potential, and great combos/kill confirms. This move has three hitboxes- early, clean, late. The early hitbox consists of the first frame, which spikes for 12%. The next frame is the clean hitbox, which spikes for 14% instead. The late hit lasts for the final two frames, dealing 12% and sending at an angle similar to BAir. When used while landing, you can combo into any of Pyra's moves, most notably DTilt, FTilt, FSmash, USmash, UAir, and BE. This also allows it to reach far below the stage, spiking any low recovery. When done this way on platforms, it can catch tall characters standing underneath and allow you to confirm much longer. DAir is also safe on shield when spaced, especially thanks to the low profile on its landing animation. You can duck under many rising aerials, especially if you follow up with USmash, which also low profiles. This move is also great for ledgetrapping and tech chasing, thanks to its great reward and how far its later frames reach. When spaced at ledge so that it catches ledgehang/ledgehop for example, the final frames will also catch ledge roll.
It is possible to connect DAir after a grounded footstool, though this whiffs on a few characters. Below is a chart of who it works on, compiled by Vision.
Hitbox Active
FAF
Autocancel
Landing Lag
Damage (base)
Damage (1v1)
Angle
KBG
BKB
Shieldstun
Shield Safety
Early / Clean / Late
17 / 18 / 19-20
66
1-4, 35+
14
12 / 14 / 12
14.4 / 16.8 / 14.4
270 / 270 / 60
80 / 80 / 85
30 / 30 / 65
5
-9