How would I make it so characters can be sliced and dismembered

I’m just wondering how would I make it so a character can be sliced in many different ways like in “Metal Gear Rising: Revengeance”.

Like this. [1] Metal Gear Rising Blade Mode & Combat Training Gameplay - YouTube

Is it an animation thing or just the way the characters are modeled? I’m extremely new to this btw.

Generally it’s both. That said, there’s some plugins in the Asset store that lets you slice meshes, but I don’t know if they work on character meshes.
If I were to do this I would model the characters such that they have parts that can be separated. When a slice occurs, replace the single mesh with the two cut-apart meshes. Multiply by how many times he can be cut up.

You can find vertex mesh manipulation in these examples.

Character slice asset:

This is the closest I found