Recusant's Sigil

"As your flesh bears the sigil, so your name shall be known as that...of a recusant."

—Xemnas to Sora, at the beginning of their battle.

The Recusant's Sigil (異端の印, Itan no shirushi, lit. "Mark of heresy") is a symbol created by Xemnas from his sleeping memories of the the χ-blade. It represents a Nobody's rejection of his or her human form. Each member of the original Organization XIII was given a new name that made use of the Recusant's Sigil.

During his Mark of Mastery exam in the Sleeping Worlds, Sora is marked with the Recusant's Sigil by Ansem, Seeker of Darkness so that the other incarnations of Xehanort can keep an eye on him. The Recusant's Sigil appears on Sora's shirt in the form of a silver "X."