|Experimental Portal Operator|
|Name||Experimental Portal Operator|
|Gender||Genderless (Male A.I.)|
|Vehicles and/or Gadgets||None|
|Occupation||Adventure Worlds Guide|
X-PO used to accompany Lord Vortech to Foundation Prime, however, he was sent through a rift to a random dimension (falling apart in the process) when Lord Vortech no longer needed him, despite his warning that the elements were too dangerous to handle safely and the pay raise he was promised. He was seen again when the player came along.
It is later revealed that Vortech banished X-PO to Vorton but was unaware he had done so. It is unclear what happened when X-PO arrived in Vorton but we know that he broke into several pieces and then linked his A.I up to the Vorton computer on the gateway. X-PO's A.I opens rifts leading to the missing gateway pieces hoping to repair the gateway.
Upon completing the level Once Upon A Time Machine in the West, and all 5 keystones for the LEGO Gateway have been collected from the previous levels, Gandalf notices several parts of the Gateway moving and hits them with his staff, causing Batman to ask if he broke the Gateway, until Wyldstyle realises the Gateway is still working perfectly, making Batman wonder what the extra pieces are for. The Player must take off some pieces from the LEGO Gateway (physical) and build a model of X-PO. After being rebuilt, he then explains the situation to the player and enlists them to gather all of the Foundation Elements before Lord Vortech and his forces do.
- He and Lord Vortech are among the few characters that are exclusive to LEGO Dimensions.
- He is voiced by Joel McHale.
- His name is short for "Experimental Portal Operator".
- Given his role in the game, X-PO's name could be a play on the word 'Exposition' meaning to reveal information on subjects encountered in narratives.
- If the subtitles are on during the opening cutscene with Lord Vortech and X-PO on Foundation Prime, X-PO will be labeled as an "Unknown Cubic Component".
- Before X-PO is repaired his A.I is coupled with the LEGO Gateway and he is referred to as the "Gateway Keeper". He controls the Gateway to open rifts to the missing Keystones and helps the trio in their journey by sending them Keystone Activators to solve puzzles.
- He is the buildable figure in the in the LEGO Dimensions Starter Pack.