Horsebreaker Training (3.5e Feat)
From D&D Wiki
Horsebreaker Training [General, Fighter]
Since Large creatures would only take a -4 penalty for wielding a Huge two handed weapon, Horsebreaker Training negates the penalty entirely for them.
Powerful Build or Monkey Grip reduce this penalty down to a -2. If combined (DM's discretion as neither description outright states that they can't be), the penalty is negated entirely.
Creatures of Huge size or larger do not need this feat.
A 16th level Warmain (Arcane Evolved pages 88-91) does not need this feat since his class feature Weapon Size Increase allows for it anyway. He can take it anyway if he wishes to wield a horsebreaker earlier with just the penalty. Horsebreaker Training does not stack with Weapon Size Increase, but it overlaps so the remaining penalty is negated upon gaining the class feature, which also extends to all weapons.While it is extremely rare for a Small creature to want to train to use a horsebreaker, it is not entirely unheard of. If the creature is Small, they normally would take a -12 penalty (if proficient) for wielding a huge weapon, which would also normally mean they can’t wield it at all. As such, a Small Creature who takes this feat wields the horsebreaker (and is proficient with it) at a -8, with Monkey Grip or Powerful Build reducing it to a -4 and to a -2 with both Monkey Grip and Powerful Build (if allowed by the DM)