MochiSweet

http://i.imgur.com/AeshUnl.gif
Attack his left side(your right) as much as you can. Smash or any skills that can flinch will stop his AOE.

Rage conductor will work also.

yep avoiding his mace worked out for me. I even didn't need to RB him, just flurry and warp

hm, cool. Can i use my own avatar now?

My current build : http://tinyurl.com/jtgqkqv
This is for high attack/def/crit (don't have gold to change the bal infused ring into crit yet tho).
You can change the journeying to enthu and use another fast on accessories for more spd/change ECB to Cat brooch depends on which stat you prefer spd or crit/change temporal to wb for more spd/some ppl use valor or bloodlust as weapon suffix instead of judgement for more spd/bal. You can also use immoral instead of righteous if you haven't crit capped yet.
Others are decent for not only Arisha but most characters.