Harlequin is a member of Les Dernier Quatre, known as the Faceless Court Jester. When Faceless becomes trapped in space, Harlequin attempts to abduct Eleonore and make her his wife, but his scheme is thwarted by Narumi.
At first glance, Harlequin appears to be a silly white demon who speaks gibberish and has an absurd voice. However, he is one of Faceless's most devoted automatons. Despite being perceived as foolish, Harlequin is dangerous due to his ability to manipulate the weather. His cruelty is evident when he tried to drink a child's blood during his forced marriage attempt with Eleonore.
It has been revealed that Harlequin harbors a hidden side which does not tolerate mockery. This was demonstrated when Pantalone laughed at him for declaring his intention to marry Eleonore. In response, Harlequin lost his composure and furiously attacked Pantalone.
