- "Guardian" redirects here. You might also be looking for the Guardian of Forever.
The Guardians work under the auspices of the Symbiosis Commission. They serve the symbionts by maintaining the underground pools that nurture them, such as those in the Caves of Mak'ala on Trill. Timor was a Trill Guardian in the 2370s. (DS9: "Equilibrium")
The Guardians also serve the well-being of the symbionts after they are joined, and help the new host adjust to preserve that well-being.