Snake's Nair is a weird one, i can't really explain it but Calzorz always knows when to use his Nair. He won't drop from the air obviously with it cuz i can just re-act and counter, depends what position im in. BUT YES, HE DOES SOMETIMES APPROACH WITH NAIR, usually he times a grenade, then he can shield just after the FH Nair grabbing the nade and also shielding before the nade blows up. What Nair will do is push Marth back abit, and what Marth's tend to do is run in and sideB the lag from the Nair, htting Snake but also the nade hitting Marth. There's something else i could say but i cant explain it properly.