Titanfall: Titan Unmanned Guard Mode
Titans can be set to an unmanned guard mode
In this mode, the Titan will be controlled by the AI and guard the area it is assigned to
When you leave the Titan, it will act on its own. You can either have it stand guard, or follow you on the battlefield.
Even though the Titan is unmanned, it can still be killed like a regular character, and it will not respawn.