... I guess he's not feeling very talkative today. No worries, I'll do the lore dump.
content warning: extreme childhood trauma, loss of family/siblings in childhood, war, violence, mentions of gen0cide.
Jupiter is a human that lives on Machina. He was a middle child who idolized his big brother Jovian and was very close with his siblings and parents. They lived a peaceful life as engineers and mechanics, often building their own transportation vehicles or other inventions to help them with daily tasks. His mother was a skilled mechanic while his father was one of the best engineers on the planet.
But one day, a race of aliens called the Kili Lege carried out a brutal attack, attempting to wipe out all the humans on Machina in order to colonize the planet. They almost succeeded. Jovian sacrificed himself in order to save Jupiter and told him to protect their younger siblings at all costs. He was killed in a gruesome manner in front of Jupiter, along with the rest of their sisters and brothers. He couldn't save any of them.
However, right as Jupiter was about to get killed, a giant gundham appeared in the sky and wiped out the Kili Lege, effectively halting the attack. Jupiter never found out who the pilot was, but this heroic act left an imprint on him.
There were only a handful of survivors from the tragedy on Machina. They banded together and formed the Junk Crew, eventually electing Jupiter as their leader due to his excellent leadership abilities and good rapport among its members. In the decades since the attack, they successfully completed reconstruction and now have a self-sustaining community with greenhouses, electricity, indoor plumbing, solar panels, scientific labs, and more. They often have to defend themselves from outside attacks led by rival crews, such as the Clankers, who wish to steal their resources and implement anarchy in the region.
Nowadays, Machina is treated as a dumping ground for the universe's most unwanted. Shipments of garbage and trash arrive weekly. The Crew does daily scavenges where they recycle as much waste as possible for other uses to try and reduce pollution. Sometimes even people are thrown out, as well. Unwanted children, disabled people, those with mental illnesses, and former babydolls/sex workers are brought to Machina whenever they are deemed useless. When new "dumpees" are found in the Junkyard, Jupiter takes them in and helps them assimilate into the Crew. It doesn't matter who they are, where they came from, or what their physical or mental capabilities are. Jupiter accepts them all. Currently, there are a couple hundred members of all ages and backgrounds.
His closest comrades are Callisto, Europa, and Io. Callisto is a computer whiz, Europa is the resident biologist, and Io is an expert on alien technology and language. However, despite having known each other for years, Jupiter still struggles to open up to them. He tends to keep to himself, and when he's not carrying out his duties as the leader, he can often be found alone in his workshop or wandering aimlessly around the Junkyard.
Jupiter is attempting to build a gundham of his own, in order to ensure that the tragedy of the past never happens again. However, there have been several setbacks in its construction, mostly when it comes to powering the thrusters. He hasn't been able to find a suitable power source with enough energy to run the gundham. That is, until he meets Star.
Because of what happened, Jupiter has a deep disdain for alien races/non humans. He refuses to accept help from the Galactic Federation, believing that they abandoned the people of Machina when they needed support the most. His hatred for interstellar species is challenged when he meets Star, causing a conflict within him when he starts to fall in love.
The denim jacket he wears was his older brother Jovian's. It's one of the few things he has left of him. He rarely takes it off or wears other things. His style is inspired by punk culture. He likes piercings, DIY projects, punk rock, and punk pop music.
In Earth years, he's somewhere in his early to mid thirties.