The Bone Whistle in Wuchang Fallen Feathers is a special item used to summon NPC companions to help you during specific boss fights and enemies. In this article, I’ve covered how to get the Bone Whistle and how to use it.
How to Get Bone Whistle

You can get the Bone Whistle by completing a task with an NPC named Nian Suichang. You meet Nian after beating the first big boss Man-Eating Dhutanga. After that, go to the Narrow Stretch area and find him. If you agree to help him out, he will reward you with the Bone Whistle.
There is another option to get the Bone Whistle. You can buy it from a merchant named Tao Qing. To do this, you need two things: 500 Red Mercury, which is the in-game currency, and an item named the Priest’s Broken Cane. Trade these with Tao Qing, and he will give you the Bone Whistle.
How to Use Bone Whistle

Just having the Bone Whistle doesn’t mean you can call for help anytime or anywhere in Wuchang Fallen Feathers. You can only summon your NPC friends during certain boss fights or enemies. The game will show a notice at the bottom of the screen when it’s the right time to use the whistle.
When you blow the Bone Whistle, there’s a few seconds of animation before your ally arrives. Because of that, it’s best to keep the whistle in your quick access slot. That way, you can use it right at the start of a tough fight without any delay.
Now that you know how to get and use the Bone Whistle in Wuchang Fallen Feathers, you have a powerful way to summon NPC companions to help in tough boss fights.