Leg. Marth build?

A speed bane is unfortunate but you can easily compensate by running him with field buffs.

I think I have to agree with kaeporo. Aside from the slaying edge build (for which I have a distaste because I think Ayra's better at that build), I don't find the offensive builds that convincing with -spd unless he's receiving hone spd, in which case I think anything goes. 39 spd with fury is not, in my opinion, enough for a unit that wants to take the fight to the opponents.