Animating a non-fixed 2D character

[iSyntaxis (Synulux)]

How would I animate a non-fixed (that can be modified differently with character customization) 2D character? Like this:

This is the Roblox game of the attachment above, and I would like to know a base idea of how they did it: Gacha Online ✨ - Roblox

I’ve thought about doing it frame-by-frame however, since it allows character customization, I don’t think it’ll be kind of possible…

[Cinnamisu]

this is probably a billboard gui and a bunch of imagelabels, you can see that the limbs images have caps on them so they look “connected” when bending

you could animate this by setting an anchor point wherever you want the parts to be connected and rotating the imagelabels

so it works just like a roblox character but in 2d

just remember that 2d images hate semi-transparency and will render “behind” such objects.