HP is increased by 16/20/24/28/32%. When there are opponents nearby, the DMG dealt by the wielder of this weapon is increased by 20/25/30/35/40%. This will take effect whether the character is on field or not.
In Game Description
The Qilin are benevolent by nature, and will never harm another soul, save by necessity.
I assume this is Qilin Bow/Kirin Bow which has been leaked (only name) before
How to Get Aqua Simulacra?
Obtainable from limited weapon banner
Aqua Simulacra Weapon Upgrade Materials
Here’s all material you need to upgrade Aqua Simulacra: