The game has no explicit rule that demands something dead for prototyping. But in practice, the kernelsprite has particular attraction to the deceased or the doomed. Across every session ever played, exceptions to this pattern are extremely rare.
Hey check it out. Every week we'll be revealing some new troll characters from Hiveswap until Act 2 is out. Follow the Troll Call here, and meet the first two here. Expect a few more surprises like this to drop in coming weeks.