About Yami Yami no Mi
The Yami Yami no Mi is a Logia-type Devil Fruit that allows the user to create, control, and transform into darkness at will, making the user a Darkness Human (闇人間, Yami Ningen?, English: "Darkness Man"). It was eaten by Marshall D. Teach, also known as "Blackbeard", who stole it from Commander Thatch of the Whitebeard Pirates' 4th division after murdering him.
This fruit is considered unique even for a Logia, and the ability it grants is said to be the "most evil" of all Devil Fruits.
The Yami Yami no Mi is a large, round, light purple fruit made up of many small teardrop-shaped components with swirl patterns, and green leaves sprouting from the top. Its overall shape and appearance closely resembles a pineapple or a bunch of oversized and teardrop-shaped grapes.