X (disambiguation)

X or χ (the letter "chi") may refer to:

• The χ-blade, a legendary weapon introduced in Kingdom Hearts Birth by Sleep.
• The Recusant's Sigil, which is represented by an X.
• Luxord, number X in Organization XIII.
• Subject X, a mysterious girl first mentioned in Kingdom Hearts III.
• The χ series, a subseries of Kingdom Hearts prequels.
• Kingdom Hearts χ, a Kingdom Hearts game exclusive to PC browsers.
• Kingdom Hearts Union χ, a Kingdom Hearts game exclusive to smartphones.
• χ3, a community feature in Kingdom Hearts Union χ.