You have an extra set of arms.

Each extra arm has a small chance to score an additional melee attack whenever you perform a melee attack with your mainhand.

According to the skill description each extra arm has it's own chance to hit. This implies that the chance for at least one arm to attacking is:


where p is the bonus attack chance for each individual mutated arm.

(note: your natural offhand attacks (if any) are not included. )

Lvl Arm Chance

Chance of at least one bonus attack

Bonus attack average chance
1 8% 15.36% 16%
2 10% 19.00% 20%
3 12% 22.56% 24%
4 14% 26.04% 28%
5 16% 29.44% 32%
6 18% 32.76% 36%
7 20% 36.00% 40%
8 22% 39.16% 44%
9 24% 42.24% 48%
10 26% 45.24% 52%


  • Provides 5 secondary equipment slots (2 weapons, 2 arm slots, and a hands slot)
    • Note: only non-AV or DV modifiers apply when equipping armor in secondary limb slots, such as increased heat/cold resistance or increased movement speed
    • Low mutation levels make unconventional kits like wielding a two-handed weapon together with a shield and a torch possible.
  • Scales really well with quickness, attack damage, and on-hit abilities.
  • MP upgrades scale linearly.
  • Strong Flurry synergy.


  • High MP cost
  • Equipping additional bucklers or shields would grant additional chances to block. However merely one shield AV will be added to your defenses upon blocking successfully, and you may still only block once per turn (two times with swift blocking). Furthermore DV penalties from multiple bucklers / shields stack.
    • Despite not receiving additional AV bonuses for equipping multiple bucklers or shields, you will still receive their DV penalty, unlike when equipping additional armor in your secondary feet and hands slots.