Kags, or reactive if healing, or even seducer for regen.....black rose not so much on mag imop, i prefer it on a stam. storm knight is also very handy in open world pvp, and lastly dont forget about clever alchemist hvy for burst dps and julianos hvy for sustained dps with a boost in crit which is desperately needed in hvy. I have been a hvy magplar since the beginning of the game and it is effective if built right.
"Stendarr's mercy be upon you, for the vigil has none to spare."