Tommy Walker leads Council Unit and commands operations in Londinium. He has short blond hair and wears a blue suit. His significant actions commence when he finds and transports Mu to Londinium. There, alongside Ace, he persuades her to join a Christmas performance staged as a tribute to the legendary Jimi Stonefree. Tommy presents Mu as Jimi's sister and instructs her to portray Jimi during the event. His underlying plan is to artificially recreate the circumstances of Jimi's disappearance to bring him back.

During the performance's finale, Tommy sprays Mu with a substance called Purple Haze, rendering her compliant. This reveals his true objective: to transform her into Jimi's replacement. He orders her to destroy an approaching mass of Earless, the mysterious lifeforms threatening humanity. Tommy's broader strategy involves initiating a second Project Freedom to harness the Earless and increase Londinium's power.

As this plan unfolds, Mu discloses her true identity as the King of the Earless, not Jimi or his sister, and kills Tommy. His role positions him as a staff officer trusted by Field Marshal Ace, commanding the Council Unit forces within Londinium. His portrayal consistently depicts him as untrustworthy, particularly in manipulating Mu and deceptively orchestrating the performance.

The character's name and narrative function draw inspiration from the protagonist of The Who's rock opera *Tommy*, reflecting the series' incorporation of rock music references. His entire trajectory—from recruiting Mu to his betrayal and demise—occurs exclusively within the main series episodes.