I used Shuma before but didn’t really explore him alot. Lately though, after seeing some changes, I’m considering picking him up.
One assist I think might be helpful is Chun-Li’s lightning legs to hold them in place after a extended combo OTG, along with a lockdown for Chaos Dimension. These are just theories though, I’ll experiment and see if I can find more things
Me personally I use Firebrands M demon missle and Stranges Bolts assists to cover different approach options as well as decent combo extenders for not just Shuma but for the entire team. for an air M mystic smash approach, I shall use Firebrands assist, for a wave dashing approach or for airborne opponents, I use Stranges assist.