TV-Series
Description
BT is a female Wavemaster who plays the online game The World during the events of.hack//SIGN. Her character avatar has blonde hair, green eyes, and wears light green robes complemented by a gold circlet on her forehead and a blue gemstone brooch. Notably, her character lacks the visible wave patterns commonly found on other magic users in the game.

Behind the avatar, BT is played by a woman in her late twenties named Machiko. In the real world, she is a former model who now works as a career woman at a dispatch company in the Touhoku region. She works overtime and typically plays the game late at night. Her good looks have ironically caused men to keep their distance, and she lives alone in an apartment. Despite some self-imposed isolation, such as tearing up an invitation to a class reunion, she has enthusiastically met certain other players in person. Her character name BT is derived from the BLT sandwich, having removed the lettuce, which is her least favorite ingredient.

BT is a difficult and intelligent woman who approaches The World primarily for human interaction and the relationships that can be created, seeing the actual gameplay and monster fighting as a secondary goal. Because of this mindset, she is only a mid-level player, not weak but not exceptionally strong either. She is a solo player by nature but enjoys teaming up with strong male characters such as Crim or Bear. She finds younger people, especially young girls like Mimiru, very annoying. BT enjoys crafting complicated schemes and can be manipulative, sometimes forming friendships only to achieve a specific purpose. She is very skilled in arguments, often besting other characters with her sharp tongue and calculating nature. Despite her cynical exterior and a tendency to act for her own gain, she has moments of vulnerability and a hidden capacity for kindness.

BT's primary motivation in the story is not Tsukasa and his strange condition, but rather the search for the legendary item known as the Key of the Twilight. She believes finding this item will bring her some form of benefit or satisfaction. She pursues this goal with a focused, almost detached, determination.

In the story, BT plays an interesting role as a schemer and an information broker. She forms an alliance with Crim to search for the Key of the Twilight and also collaborates with the dangerous Twin Blade, Sora, to gain valuable information. Their search leads them to the Hulle Granz Cathedral, where they open the Twilight Eye, granting access to a strange, upside-down dungeon. BT reaches the top of this dungeon alone and discovers an AI copy of the game's creator, Harald Hoerwick, an experience that deeply shakes her. After this lead goes cold, and following a failed attempt to start a real-world relationship with Crim, who prefers to keep reality and the game separate, BT becomes depressed and briefly considers quitting The World. She decides against it, choosing to remain as BT for a while longer. She later becomes somewhat friendlier to Tsukasa after he unexpectedly saves her from a group of Player Killers who had lured her into a trap. BT also has a significant conversation with Subaru, the leader of the Crimson Knights, where she angrily criticizes Subaru for allowing personal feelings to interfere with her role as a figurehead, an exchange that influences Subaru's decision to disband the Knights. Eventually, BT is called upon to help in the plan to awaken Aura, using her magic to defend Tsukasa and Subaru from a powerful Twilight Guardian.

BT has several key relationships that define her actions. She is on friendly terms with Bear, and the two have met in the real world on multiple occasions. She works closely with Crim in her quest for the Key of the Twilight, and while she attempts to deepen that relationship romantically offline, she is rejected. She uses Sora as an information source. She finds Mimiru annoying and views Tsukasa with initial indifference, though her attitude toward him softens after he saves her life. Her confrontation with Subaru is a pivotal interaction that highlights her pragmatic and often harsh view of responsibility.

Throughout.hack//SIGN, BT develops from a cold, self-serving player obsessed with the Key of the Twilight into a more complex figure. Her failed attempt to connect with Crim in the real world forces her to confront the boundaries she has set for herself, leading to a moment of genuine depression and self-reflection. Her decision to continue playing as BT is a quiet act of resilience. Being saved by Tsukasa, whom she had previously dismissed, forces her to reevaluate him and, by extension, her own detached methods. By the end of the series, she is still clever and sharp-tongued, but she becomes a more reliable ally, contributing to the group's final plan to help Tsukasa and Aura rather than simply pursuing her own goals.

As a Wavemaster, BT is proficient in both offensive and defensive magic. While she is a capable spellcaster, her true notable abilities lie not in raw power but in her intelligence, her skill at manipulation, and her talent for creating intricate schemes to gather information and get what she wants from other players.