Nightlace

...from his flesh, he took drops of his blood and added them to the soil around the tree. Dark lines etched their way up the trunk, spiraling around the branches. On some, small fruits began to grow like flowers, the dark lines fading with each one. He reached up and plucked one from the branch, pulling out a knife as he did. Cutting it open revealed the dark lines hidden within...

— from 'The Legends of the God-Crafted'

Nightlace is one of the rarest fruits in the Ghoul Realm. The name nightlace comes from the strange pattern on the inside of the fruits which resembles both lace and the patterns often depicted on the clothing of the God of Death, making it considered hand crafted by the God himself.
It is used during the decennial celebration for the God of Death, called the Festival of Nightfall. During the start of the festival, an expedition is sent to the largest grove of Grim Medlar trees, carefully cultivated for this purpose, to harvest as much of the fruit as possible while not harming the trees themselves.
From there, the majority of the fruit is either turned into jelly or into a stew. On the final day of the festival, the untouched fruit is offered to the God of Death while the rest is eaten over the next few years. Outside of the festival, nightlace is eaten rarely, often only when it is found from wild trees.

Properties

Material Characteristics

Nightlace is about the size of a child's fist, between 1 to 2 inches in diameter. The skin of the fruit range anywhere from a dark blue to a dark purple, while the inside is a lighter shade and threaded with pitch-black veins in a lace-like pattern.