Tsil, also known as Spook-Crystals or Smokies, were mineral based life forms that resided on the planet of Nam Chorios. Oldtimers, descendants of the planet's original Human settlers, gave the Tsils their names and nicknames, and were unaffected by the electrical storms they produced. Offworlders caught in the five-to-ten minute electrical storms that the Tsils created, were left sick for about a day and a half. The Guardian crystals were the largest of all the crystal variants; this made them capable of controlling the smaller crystals.