I saw kidsoul being called symmetricool which felt very surface level to me eventhough it's funny as a pun. I think jazzbalance (as in 'just balance' like in christianity) is much cooler, perfectly summarized their characters' arcs, and how they are both the Grim Reaper and his Death Scythe and God of Order and the Conduit of Harmony (how the scythe is also a piano that connects souls to work synergistically).