Chain Sumeragi is a supporting character in the anime and manga series Kekkai Sensen (Blood Blockade Battlefront). She is a member of the secretive werewolf agency and works alongside the main cast as an invisible werewolf. Known for her calm, stoic demeanor and sharp wit, Chain excels in stealth operations thanks to her unique ability to become invisible. Despite her aloofness, she is highly competent and reliable, often assisting the Libra organization in their various missions throughout Hellsalem's Lot.