Fumiko no Chichi

Fumiko's father initially presents himself in an intentionally unpleasant way, making crude comments and describing himself with a sexualized label that gives Tae good reason to distrust him.

His actions gradually contradict that first impression. He repeatedly helps Tae through the alien city, remaining beside her when abandoning her would be easier and safer.

The motivation behind that behavior is kept hidden for much of their time together, making his persistence difficult for Tae to understand.

Fumiko's father is an ordinary human with no supernatural abilities, Gantz suit or advanced weapons.

He survives through practical judgment, persistence and willingness to move through dangerous areas alongside Tae. Compared with the Gantz hunters, he is extremely vulnerable to the invading aliens and their technology.

His most important strength is therefore not combat ability but his refusal to abandon another person despite having no special protection himself.

Fumiko's father enters during the Katastrophe, when Tae has been separated from Kei Kurono and is struggling to survive among captured humans inside the alien civilization.

He becomes her unlikely companion and helper. His crude statements initially obscure why he repeatedly places himself at risk for a teenage girl he has only recently met.

It is eventually revealed that Tae resembles his deceased daughter, Fumiko. His determination to protect her is driven by that resemblance and by the chance to do for Tae what he can no longer do for his own child. He dies helping Tae survive, and his personal name is never revealed.

Tae Kojima becomes the person Fumiko's father protects during the alien invasion. He ultimately reveals through his actions that Tae reminds him of his deceased daughter rather than being merely the object of the crude interest he initially claims.

Fumiko is his daughter. Her death predates his encounter with Tae, and Tae's resemblance to her explains why he becomes so determined to keep the younger girl alive.

Kei Kurono is the person Tae is desperately trying to reunite with, making Fumiko's father's assistance indirectly important to her attempt to find him.