Key of Khaj-Nisut
Key of Khaj-Nisut is a Sword in Genshin Impact that boosts Maximum HP and Elemental Mastery based on Maximum HP! You can get the Weapon via Wishes. Its special effect is Sunken Song of the Sands:
HP increased by 20%. When an Elemental Skill hits opponents, you gain the Grand Hymn effect for 20s. The effect increases the equipping character’s Elemental Mastery by 0.12% of their Max HP. This effect can trigger once every 0.3s. Max 3 stacks. When this effect gains 3 stacks, or when the third stack’s duration is refreshed, the Elemental Mastery of all nearby party members will be increased by 0.2% of the equipping character’s max HP for 20s.
Builds that can use this Weapon are: