Kāma

The kāma is a mark that takes the shape of a black diamond on the user's hand. Although unfamiliar to the population at large, Kara has knowledge on it and similar seals. According to Koji Kashin, the mark is directly connected to the defeat of Momoshiki Ōtsutsuki.

So far, Boruto Uzumaki, who received the mark after defeating Momoshiki and Kawaki, who received it through unknown means are the only known wielders.

Usage
After unconsciously activating it, Boruto was capable of absorbing ninjutsu. As it was his first time accessing the mark's power, it made him collapse afterwards. Three years later he could activate it at will.

Kawaki is able to absorb flames and cause large-scale explosions with his Kāma. However, using the mark causes his body to overheat, leaving him unconscious. Three years later, he is able to willingly activate it as well.

Boruto's and Kawaki's marks are connected by, similar to a tube. It apparently enables them to release anything that either of them previously absorbed.

Trivia

 * Although the kanji itself would normally be translated as, the furigana indicate the reading . "Kāma" means "wish", "desire", or "longing" in Hindu literature. In Japanese it is also an uncommon way to write "karma".

pt-br:Kāma Karma Kāma