Slash Gaira →↓↘ + Slash, and Bust Gaira ↓↙← → + Slash get powered at POW max.
Slash Gaira can so his ←↓↙ + Slash, and Bust Gaira his ↓↘→ + Slash while he is weaponless. Both can do their (jump) ↓ + Any.
Bust Gaira ↓↘→ + Slash can deflect horizontal projectile or just absorb them if done as they are very close to hurt him, beside those of Hanzo (powered), Bust Amakusa (powered), Bust Rimururu and Slash Amakusa (powered). As for the others, some can only be absorbed while other will be deflected.
Gaira (jump) D is cancelable with ↓ + Any.
Some characters (currently Hanzo and Bust Haomaru) can perform umblockable after they juggled him on corner. This could be related to the fact that that gaira take an additionnal frame before recovering once he touch ground, and if the character is fast enought he will be able to take advantage of it. Example: Bust Haomaru: (←↓↙ + Slash, close standing A, ↓ + B, super move), Hanzo: ( ↓ + B, ↓↙← + Slash, Rage explosion, ABC, ←→↘↓).
Gaira weapon seems to posess two connecting points on a standing medium range falling C slash and that actually strike with the property of a blade (you can hear a sound similar to charlotte standing B). This mean that both ninja can do their replica attack (log technique) as a counter on that move. It could be related to the fact that the part which is connecting is the purple edge of his weapon.