Jarren was the human slave, or lo'taur, in service of the Goa'uld System Lord Yu.
When the System Lords decided to form a new order, they agreed to arrange a summit to which each System Lord was permitted to take one lo'taur. Jarren was Lord Yu's selected lo'taur. He had recently gotten into this coveted position by the death of Yu's lo'taur in a surprise attack against Yu's base.
Jarren was not able to go with Lord Yu to the summit, however, because Daniel Jackson took his place. Jacob Carter and his Tok'ra symbiote, Selmak, were able to gain access to Yu's palace as a minor Goa'uld in the System Lord's service and replace Jarren with Daniel Jackson with the use of a chemical injected into Yu which gave the illusion that Daniel was Jarren. Daniel learned much about being a lo'taur while acting in Jarren's place at the summit.
--DeeKayP 18:58, 6 Jul 2004 (PDT)