@DivinityDuring my thinking I also realized that before his recent rework that most Shards didn't exist as entities. So I had to come up with what happens to them, and I figured that:
Cell Shards: Are parasitic to the host body of the Shard they're inside, they feed on the psychic energy of the host so they don't need the Divine directly. But once they are singularly separated they nearly instantly die.
(Cell shards form the red-black cloud that is controlled by all Shards.)
Richter Shards: Become primal and brainless, they cannot think for themselves and effectively become loping monsters that consume flesh in a vain attempt to fend off psychic starvation. They lose the ability to control Cell Shards, and that is what inevitably becomes their demise, as the Cells feed on them until the Richter cannot sustain body functions. Richters gradually lose physical durability over a long period of time, and cannot heal from wounds.
Baron Shards: Are a balance between Richters and Wanderers. Richters don't consume much psychic energy, Wanderers consume too much. Baron's consume exactly enough energy to be "fuel efficient." They do, however, become intense psychotic sadists. They want the juice straight from the source and will antagonize and torture victims to suck the psychic energy straight from their heads. Their bodies do lose some of their durability instantly, but after the initial wave of body failure they don't collapse in on themselves. Their movements become violent and erratic.
Wanderer Shards: Consume an immense amount of psychic energy, their size and composition is so dense and massive that without a constant stream of psychic energy, they cannot sustain it. Their bodies erupt in plumes of smoke and their flesh breaks away from their body, their bones break and their minds are flooded with an unbearable pain. Their last moments are spent in total agony and they leave behind an unbelievable mess.