Tellus was a former Zion operative and one of the protagonists of The King Of Never Return.
Tellus belonged to a group of three Zionites - the other two being Phoebe and an operator Europa - who grew unbearably dissatisfied with their life in the Real World. Instead of living an ascetic and powerless existence underground waiting for The One to save them, they chose to steal one of Zion's battleships and run away, spending their lives broadcasting into the Matrix and living out whatever fantastical scenario brought them most entertainment and adrenaline on that specific day, with intentionally taunting Agents only to run from them being a particular favourite.
Tellus and Phoebe were robbing a bank in Mexico while (on Europa's suggestion) pretending to be cowboy gunslingers for little more reason than simply "kicks." All three died during a subsequent confrontation with two Agents - while the Agents occupied the crew's attention, a Zionite hovercraft in the Real World noticed the stolen ship and opened fire, reclaiming the stolen vehicle but killing its rogue crew.