The Fabled Masamune (Tier 5)

When Weapon Durability is above 50%, for every 1% higher, Crit DMG +3%, up to +120%. When Weapon Durability is below 20%, for every 1% lower, Attack -2%. When dealing a quick attack after drawing weapon, Attack +30% and guaranteed critical hit (ineffective against Metas). Can be triggered once every 15s. If the quick attack hits, the enhancement effect will stay for 5s, but will decay over time.