History of Kairos Function Mark

Overview

The Kairos Function Mark is a Legendary Titan Mark for Titans and one of the class items of the Kairos Function Suit, a Legendary armor set from Destiny 2: Curse of Osiris with versions for Hunter, Titan and Warlock. The set's lore is written as research on the Vex.

The mark's flavor text reads: "Some speculate that the radiolarian fluid is the last vestige of a biological life-form that became the Vex." —Sister Faora, "Theories on the Vex"

Acquisition

Xûr sells the mark. The set can also be earned through rank-up packages from Brother Vance, and it is not a loot drop. Xûr's stock rotates, so the mark is only available when it appears in his inventory.