One armed master

When you take this feat, you may choose one versatile or two-handed melee weapon.

If you choose a versatile weapon, you deal damage as if wielding the weapon with two hands, even if you are only using one hand. You receive a -1 to all attacks rolls made when wielding a weapon in this fashion.

If you choose a two-handed weapon, you can wield this weapon with one hand. Doing so gives a -3 to attack rolls, but deals regular damage if the attack lands.

You can only use these features if you using a weapon in one hand, and no weapon in the other. You may still use a shield and gain these benefits.

You cannot gain sneak attack damage when wielding a weapon in this fashion.

You may take this feat one additional time, choosing a different weapon each time.