Forceful

Source Core Rulebook pg. 282 2.0
This weapon becomes more dangerous as you build momentum. When you attack with it more than once on your turn, the second attack gains a circumstance bonus to damage equal to the number of weapon damage dice, and each subsequent attack gains a circumstance bonus to damage equal to double the number of weapon damage dice.

Equipment

Impactful, Rebounding Breastplate

Monk Unarmed Attacks

Falling Stone, Flashing Spark, Gorilla Slam

Weapons

Adze, Elven Curve Blade, Falchion, Glaive, Hand Adze, Orc Necksplitter, Scimitar