Pioneer

Pioneer is a humanoid "catgirl" character introduced in episode 5 of Humanity Has Declined. She is first introduced as Pion, but is actually the unmanned space probe Pioneer given human form.

Appearance
Pioneer is depicted as a young girl with light, blue hair and large, cat-like ears using the same color as fur. She has blue eyes and wears a science fiction-themed outift that mixes white with blue colors. This outfit includes gloves that extend all the way to her upper arms. She also wears a light-red scarf.

Personality
Pioneer is a character who takes her role as a satellite seriously, but in doing so attempts to obfuscate the fact that her mission scares her. Upon her return to earth, she comes to see The Mediator as a leader and begins to follow her around when they become lost in a large facility. While Pioneer has amazing strength and can operate complex systems, she relies on receiving orders from others and keeps addressing the main character as "commander".

Though she wants to reunite with her companion Voyager, she is upset to find that he is unwilling to resume their mission and the two wind up fighting. Upon regaining all their memories, Voyager reasons with Pioneer that her upbeat and loyal attitude prevent her from expressing her true feelings, causing her to burst out in tears.

Pioneer has a quirk where she uses sound-effects to indicate when she has come to understand a new piece of information.

Background
Pioneer is first found as a tablet that has crash-landed in the vicinity of the village. When they start using electricity, Pioneer is recharged and begins wandering the town. At this point, her memories are scrambled and she believes herself to be called Pion. In the village, she meets the main character and asks after her lost companion, Oyage. Later on, her tablet turns up in the labyrinth of the facility and is recharged again when it's used to fend off a slime monster.

Together with The Mediator and her assistant she traverses that hallways until Oyage is found. When Oyage turns violent and attacks the party, Pion retaliates and eventually defeats Oyage by using a supercharged microwave. The effects of the microwave cause their recovery systems to kick in and restore their memories, allowing Pion to realize her true name and identity. After leaving the facility, everybody is picked up by the protagonist's Grandpa.

The discovery of Pioneer and Voyager is celebrated by the members of the UN, but Voyager is not at all excited. He reveals that their mission was harsh, cold, and frightening, for which Pioneer chastises him. However, Voyager points out that it was Pioneer who suddenly decelerated during their mission and followed him to earth, leaving her in tears. After admitting she too does not want to return to space, The Mediator sabotages the UN's generator and allows Pion to run out of electricity. In their final moments together they devise a wind-up mechanism, allowing Pion and Voyager to occasionally wander around in their human forms.

Trivia

 * Pioneer's character and arc reference the Pioneer satellite program, which ran into an anomaly where the satellite unexpectedly decelerated during its unmanned mission. Her companion, Voyager, references the Voyager satellite program.