The Megami Tensei games let you fuse demons. The idea behind this is to let you track all your fusions so at the end of the game you can go back and see where your current demons came from. Inspired by that bit from SMT3: Nocturne (you know what I'm talking about if you've played it; if you haven't I won't spoil it).
I'm using the Seed framework for Rust frontend web development. The project was initially created based on the seed-quickstart template.