Jack (the box) and Casie (the... whatever she is) ('human' extremely tall airquotes) are a dynamic duo looking for their master, who has ''''mysteriously'''' gone missing during an exploration in a ruin of the Ancients
jack is basically just a walking, snarking inventory. like, you can put things inside him. his maximum capacity is something like casie's body weight, so theoretically you could just put casie in there and call it a day or you could put like a hundredish pounds of things that are actually useful in him and casie can just walk
casie is a researcher's assistant. she's like an intern. you could boil her down to just being very excited to be out walking around and doing things and not filing research paperwork
plus, she gets to play with magic
at some point i was considering having casie just be a human but then i realized she's just a forgetin cartoon character so she eventually became tom the cat
