I have seen one who possessed a shard that repelled the undead; the creatures could not pass through the odd bubble surrounding them.

[One of his own crew, in fact, though he doesn't say as such. That has to remain a secret for now.]

There was a strange occurence recently where a woman whom many called a 'witch' had shards in her possession that seemed to give her different powers, though I am not certain exactly what. Some speculate that the shards have different abilities depending on who holds them, or that each shard can do something different.