Animating pixel art object

I am struggling to work out how to animate a pixel art character. The character is a single object. The object is made of a mesh of cubes that have different coloured materials for the pixel art effect. Using this system, I can use the build modifier to have the cubes appear in the order that they were created, like a magic apparition.
My problem is that I am trying to work out a way to animate the characters arm. In my head, the cubes should not deform but “migrate” from one position to another.
And there my logic falls to pieces. I suppose this is like a stop motion effect where some cubes are taken away and others added to simulate a movement.

I was wondering if anyone has an idea how I can do this.
Many thanks
Please note that I am a relative 3D newby.

If your cubes are seperate objects than you can easily keyframe the position of them. Otherwise you would have to assign a vertex group for each part of the mesh and assign bones to them like any other basic rig, but instead of keyframing the rotation of the bones you would have to keyframe the position of them. I’m not an animator so I may be wrong.

Thank you for the reply. The cubes are not separate objects. I suppose I could separate them. I have tried the vertex group idea but I am not getting the result I am looking for.
I found this very impressive tutorial which is the result I am looking for but I am stumped as it how to control this for animation.

In the end I have broken up the mesh into seperate objects and used the build modifier to animate them. This leads me to another problem: when I apply the modifier, I lose the animation. But this is another adventure …