Van is the reincarnation of Spike Spiegel.
Come on, there is no denying how much Van looks like Spike.
  • Alternatively, Van and Spike are long-separated siblings, and Dandy is their idiot cousin.
The Claw has already been "reformatted".
It's just a possibility, considering his inability to feel anger or sadness. His occasional killing could be an error, perhaps from a prior experiment or attempt at using the Destroyer System.