|Real Name||An Shouji|
|Real Life Gender||Female|
|English Voice Actor||Brianne Siddall|
|Japanese Voice Actor||Mitsuki Saiga|
An introverted young Wavemaster with unusual game powers. Tsukasa finds himself at the heart of a mystery about the .Hack world. Unable to leave the game, he is pursued by other players because of his abilities and at times resorts to invoking a strange Guardian to protect himself. His encounters with Mimiru are akward because of their differences.
Tsukasa is the hero of .hack//Sign, the first anime to be published of the series and the second title to take place chronologically. He is a Wavemaster. By forces unknown, he is trapped in The World and unable to log out.
Tsukasa wears a relatively simple robe with much more subtle colors than most in The World, mostly tan and brown. He always carries the same, low level staff. It resembles a metal shepherd's cane, with a red jewel floating unsupported in the head of the cane. He has two tattoos on his face.
Perhaps a result of his upbringing or of trauma experienced in The World, he has a reserved nature and is unfriendly to the entire cast at the start of the series. He's untrusting of everyone around him, and of society as a whole, but learns to respect his friends by the end of the series. His outlook on life also changes throughout the series, initially extremely pessimistic, he turns his fear of the real world into a desire to return by the end.
 Role in .hack//Sign
Tsukasa is the main character and primary plot device in .hack//Sign. Most of the cast is attempting to discover the cause of Tsukasa's inability to log out. They eventually discover the "gods" of The World, and the mystery surrounding them and come close to solving it.
 Role in Other Titles
Tsukasa appears in flashbacks in .hack//Mutation along with most of the cast of .hack//Sign. If these flashbacks were seen, the player can then use an AI duplicate of Tsukasa in their party after completion of .hack//Quarantine.
Though Tsukasa doesn't realize it, in the real world she's a girl named An Shouji. She started playing The World as a way to escape pressure in real life from her father, who is shown to abuse her. She has been on life support in a coma ever since being trapped in The World. She was most likely targeted due to her depression and fragile psyche, to corrupt Aura and prevent her birth.