With the SAM update you can build a rather nasty 6hit for Masamune.

5/5 zanshin, 5/5 med recast, 5/5 OW, 5/5 iki

Masa/sword//thew
zelus/justice/unkai/brutal
af3+2/dusk+1/raja/mars
atheling/bullwhip/af3+2/aces

Pretty hard to beat esp as you go up in haste. You can swap Mars for Pyrosoul if the acc isn't needed as well.