you can hit them from behind or shoot them with the bow from distance. use 4x conquerer periapts to maximize your damage output. important for lower level players or lower strength. when they go in ghost form, lure, agro, tank them that your caster can kill them quick. balanced builds with enchanted weapons did more damage, but not enough to kil them quick. i fought 7 living armors with my min/max level 200 assassin with periapts and blast arrows at a time. that was my hardest fight in my 1 yeared playtime ever.
Yeah, if you're open to it, an MA will utterly destroy a living armor in both forms. But if you're grounded in physical melee vocations your best bet is to have your pawns enchant your weapon and try to do as much damage as you can; though it won't be much since LAs were designed for balanced teams or at least balanced players.
Skyrim is not the holy grail of RPGs... (Plays Skyrim)... Skyrim is the holy grail of RPGs