Multiweapon Fighting( Monster Manual v.3.5, p. 304)
A creature with three or more hands can fight with a weapon in each hand. The creature can make one extra attack each round with each extra weapon.
Dex 13, Three or more hands,
Greater Multiweapon Fighting (DD) , Greater Multiweapon Fighting (SS) , Improved Multiweapon Fighting (DD) , Improved Multiweapon Fighting (SS) , Multitasking (SS) , Multiweapon Rend (ELH) , Perfect Multiweapon Fighting (ELH) , Improved Multiweapon Fighting (ELH) , Greater Multiweapon Fighting (ELH) ,
Penalties for fighting with multiple weapons are reduced by 2 with the primary hand and reduced by 6 with off hands.
This feat replaces the Two-Weapon Fighting feat for creatures with more than two arms.
A creature without this feat takes a —6 penalty on attacks made with its primary hand and a —10 penalty on attacks made with its off hands. (It has one primary hand, and all the others are off hands.) See Two-Weapon Fighting, page 160 of the Player's Handbook.