Possible, but only if they were non-homogeneous.
I'm going to work off the assumption that these are living beings. I've not an idea how such a living being would develop. So, let's discuss the Ego. This Ego would be more of a colony, rather than an entire unique organism, composed of a few different types - muscle, form, mind, and sight. (Types of what? Cells, maybe, or groups of supercell clusters.)
Muscle - these types let the Ego move. They're responsible for the blob form being able to move, and would allow it to shift shapes. Unfortunately, they'd be a bit lackluster, and wouldn't be able to give the Ego itself much strength. They'd also be reliant on the form cells to give them structure in blob form.
Form - these types are the hard parts. Literally. In blob form, they're dispersed as widely as possible, only linking with each other in rare thin, structures to allow the muscles to move the blob, than shrinking. In sword and shield form, they'd turn into the edges. (This gives you the advantage of having a sword that had a flexible middle, letting it take blows well.)
Mind - these types let the Ego give commands, telling the muscles to move around, letting the blob move and shift, and shift back from sword/shield to blob. Also dispersed, but they'd always be connected to each other, like a really flexible massive nest of nerves.
Eyes - the only single type, which lets the Ego see.