TV-Series
Description
Abuto Usui serves as a co-protagonist in the series. A young engineer at the Shinkansen Ultra Evolution Institute, he assists in refitting Shinkalions and constructing Zailiners. Though perceived as a genius, Abuto rejects the label because his engineering designs originate not from his own creation but from blueprints transmitted directly into his mind by his father through an unknown method. These transmissions often manifest as dreams that also feature a mysterious Dark Shinkansen and provide clues to Z Code locations.

Quiet and stoic, Abuto contrasts sharply with his energetic counterpart, Shin. Highly intelligent and athletic, he sometimes evades Shin's questions. Despite his reserved nature, he cares deeply for his family, refusing relocation to Ōmiya due to concerns about his mother's emotional well-being. His passion for railway engineering and conventional lines mirrors his father's interests, causing him to display uncharacteristic excitement and detailed rants when discussing them. Early in their interactions, he occasionally lies to Shin, though this habit diminishes as their bond strengthens.

Abuto boards the Dark Shinkansen at Sekigahara Station seeking information about his father. Upon returning, he becomes the driver of the Dark Shinkalion and allies against the Ultra Evolution Institute. His motivations are a near-obsessive desire to locate his missing father and frustration over his inherently low compatibility rating preventing him from piloting any Earth-built Shinkalions. Under the influence of antagonists like Kannagi and Valtom, his demeanor grows increasingly aggressive and conflicted, particularly after Setsura's arrival. Valtom's manipulation amplifies his rage and sadness, enabling the Dark Shinkalion to activate Devil Mode.

Abuto returns to his original state after a defeat by Shin on Yugospia, disabling Devil Mode and reverting the Dark Shinkalion. Following this, the Dark Shinkalion evolves, freeing itself from Teoti control and allowing Abuto to pilot it without adverse effects. This resolution addresses his core motivations, facilitating a reunion with his father and fulfilling his aspiration to operate a Shinkalion. His surname, Usui, references the defunct Usui Line section of the Shin'etsu Main Line, while his given name derives from the Abt System rack railway mechanism once used there, reflecting an older Japanese pronunciation of its inventor, Carl Roman Abt.