Since it's not posted yet, effect active during WSs if <75%hp.
Also, if wearing empy+2 body: DT-1~2% & damage+1~2% (Killer effect/2 then rounded down)
Good for...magic WSs maybe
another ring that should be tossed seeing npc value is only 2 gil. not worth the inventory slot for the extremely random times you would even consider this ring as an option.