(Seen when using a pair of Rapier of Lifesteal) : Adds boost to Max HP
from off-hand weapon (25% for Dual Wield lv 0, 50% for DW lv 1, and 100%
for DW lv 2)
(Seen when using a non-crit weap in the main hand, and a crit one in the
offhand) : Adds boost to Critical chance from off-hand weapon (25% for
DW0, 50% for DW1, 100% for DW2). Set critical multiplier as max of main
hand weapon's CM and off-hand weapon's CM multiplied by {0.25 for DW0,
0.5 for DW1, 1.0 for DW2).