Baku is the Designer Child that plays host to the Planetary Gear known as Bugbear. He is the last member to be introduced and the 6th to be reawakened.

Baku is usually reserved and quiet, mostly talking with people related with him, or with those with he feels more at ease. He grows to care for Kumiko Asanoda whom he views as his savior as he believes she gave him a reason to live for after being purchased as a slave, and dedicates himself to her well-being and possibly hold romantic feelings.

He trains hard as he wants to achieve the strength to protect her at all costs and is willing to challenge higher members of the Yakuza family if it is needed for Kumiko's safety, showing his dedication and lack of fear.

He is the only member of the Planetary Gears who rejected his past memories, and only rejoins the group out of pure grief of losing Kumiko.

As Baku, he is one of the strongest characters of the series. His physical condition is several times higher than the average human, being the undisputed champion of the illegal arena, facing several armed men and winning with his mere fists without ever being wounded. His strength is great enough to defeat men larger and heavier than him in a single strike and send them flying. His combat prowess allows him to challenge Amara himself in an even match. Whenever his emotions are unstable this can cause shakes in the space, which create quakes of moderate intensity. He has a Singularity that allows him to restore anything to its previous state, as in a pile of cards or a damaged photo, but he cannot select what to repair and what not. This power can also extend to people, being able to revive them as illusion-like beings that cannot be killed, as if they are harmed, they regenerate instantly. However if this power fades, all people resurrected will vanish instantly.

As Bugbear not much is known, except that he used to spar with Amarok seemingly in even conditions.

(Source: Captain Earth Wikia)