(Edit: fixed link!)

Characters:
Xue Jun'li [OC]
Six-Eared Macaque [Lego Monkie Kid]
Reference Here!

With Xue, I'd like to think that the shadow lantern Macaque uses would have been his at first.

The lantern was originally used to guide lost souls to the Ferryman in the underworld, so that he may put their souls to rest. Eventually, the magic started to lose its light and became the Shadow Lantern that Macaque uses.

Of course, that's not how it is in canon because Xue is an OC, but I like the lore, lol.

The core power of the lantern would have been to see the true intentions of one's soul, but it can also be used as a weapon as it can hold magic. Xue would have used it to hold pure souls to harvest his magic.
Macaque used the ability to hold souls [Like what he does in the Shadow Play episode] and harvest his shadow powers.

Since Mac isn't inherently strong physically [headcanon], I think the Lantern would have enhanced his ability/strengths.

I struggled with doing the lighting, but I had just woken up from a medication-induced nap so lol