ToME WikiNo spoilers here, please.
NO SPOILERS HERE!
Symbiants live in harmony with all of the monsters that do not move; the Mushrooms, Molds, Floating Eyes, and such. Symbiants can hypnotize these creatures and then form a symbiotic relationship with them.
Once hypnotized, such a special pet is referred to as a symbiote. The symbiote may be placed onto the the body of the Symbiant (i.e. "worn") in order to initiate the symbiotic relationship.
The symbiote will sometimes fight on the Symbiant's behalf, depending on the Symbiant's skill level and the symbiote's capabilities. The symbiote will also sometimes take damage for the Symbiant, in devoted self-sacrifice. Using other, even more advanced symbiotic powers, a Symbiant may use the magical abilities of his/her symbiote.
You may name your symbiote by inscribing it (after it's worn) with '# named <name>'. This does not affect gameplay, just the messages you will see.
Starting stat modifiers, starting Skills, innate abilities and starting equipment: Please see the in-game help.