Espada de Taixu

Easier to achieve when fighting the Doomsday Beast in Echo of War. Can eat a consumable for some extra damage.

A reference to the Edge of Taixuan, a martial art technique made by Fu Hua (not currently in any of her battlesuits) in a cutscene or the animated short, "Shattered Samsara." It's an anti-Honkai martial art for regular people, with special parts that can only be pulled off if one had weapons. - Credit: Necrosyrtes