The location of the Feast Fragment Shell in Phantom Blade Zero can sometimes be confusing to players who do not know how to use the incense. Firstly, one needs to talk to Iron Finn, after which you have to head to the specified grave in Crimson Forest. This is one useful item since it will help you to get the World Breaker Feast Soul Temper for your Iron Gauntlets.
Where to Use Incense & Get Fist Fragment

Feast Fragment Shell is an item that needs to be collected to unlock the World Breaker Feast Soul Temper for the Iron Gauntlets. The Feast Fragment Shell can be collected by going to the sixth floor of Sachi Tower located in Crimson Forest and talking to Iron Finn.

While talking to Iron Finn, he will ask you to go to his grave and burn some incense for him in the Crimson Forest. In order to collect the item, you will have to go to the Burial Grounds Bell in the Crimson Forest.
Once you have arrived at the location, locate the big tombstone in the middle of the burial ground and interact with it in order to burn the incense. You will receive the item afterwards. You will not be able to interact with the tombstone before completing the request from Iron Finn.
This is just one part of the Worldbreaker Fist, as you also need to collect the Fist Fragment Core. The core is rewarded after defeating the Iron Fiend and Jade Dancer in the quest Use It Against Them. With both pieces in hand, you can then fuse them at the gravestone, then take the Worldbreaker Fist to the Myst in Pangzhen to Soul Temper it for 5,000 Remnant Dust. Once done, you will get the following effect while using the Iron Gauntlets: “Each Phantom Edge attack releases a Fist Wave forward”.

