Master Chief is a Spartan warrior who saved the world from aliens and sharks but has fallen upon rough times, so he moves into Hippo's house.
Master Chief was abducted by the government as a child, when he was forced to fight over-taxed space farmers, fight off land sharks, and stop an alien invasion. Unfortunately afterwards he couldn't find any work due to a four year gap in his resume when he was cryogenically frozen in deep space. And his military pension was cancelled after he went AWOL to chase his imaginary, AI girlfriend, Cortana
After moving in with Hippo, Master Chief had to find a way to pay rent, so he applied at GameStop but ended up trying to sell Astofol and a copy of Lego Indiana Jones 2 for store credit to the bisexual cashier. They escaped and Astofol agreed to pay his rent because he couldn't live without Master Chief. The combined cost of both rents began to financially ruin him though.
He reluctantly continued his job hunt when he needed to pay to fix the washing machine, and after Astofol painted his armor pink he applied for a job at Femboy Hooters. Master Chief and Doomguy competed for the job, but he lost because he wasn't confident enough.