The multiple attack penalty you take with this weapon on the second attack on your turn is –4 instead of –5, and –8 instead of –10 on the third and subsequent attacks in the turn.

You can use your Dexterity modifier instead of your Strength modifier on attack rolls using this melee weapon. You still use your Strength modifier when calculating damage.

These weapons are used as a pair, complementing each other. When you attack with a twin weapon, you add a circumstance bonus to the damage roll equal to the weapon’s number of damage dice if you have previously attacked with a different weapon of the same type this turn. The weapons must be of the same type to benefit from this trait, but they don’t need to have the same runes.

Something of uncommon rarity requires special training or comes from a particular culture or part of the world. Some character choices give access to uncommon options, and the GM can choose to allow access for anyone. Less is known about uncommon creatures than common creatures. They typically can't be summoned. The DC of Recall Knowledge checks related to these creature is increased by 2.