Halle Lidner, born Halle Bullook on February 18, 1980, is a former Secret Service and CIA operative recruited by the SPK to dismantle Kira’s regime. Driven by vengeance for a close associate murdered by Kyosuke Higuchi during his time as Kira, she adopts an alias to infiltrate Kiyomi Takada’s security detail, using her position as a trusted bodyguard to covertly investigate Takada’s ties to Kira while balancing public visibility from media exposure. Though formally allied with Near, Halle secretly exchanges SPK intelligence with Mello, supporting his parallel pursuit of Kira. This dual loyalty highlights her tactical flexibility, valuing results over allegiance to L’s successors. Her covert aid includes sheltering Mello and relaying Near’s hypotheses, though some adaptations alter their partnership—depicting Mello coercing her as a hostage rather than accepting voluntary collaboration. In the investigation’s climax, Halle enables Mello’s abduction of Takada, a decisive maneuver that unintentionally triggers his demise. Her acknowledgment of Mello’s critical role in cornering Kira underscores her understanding of his strategic impact. After Light Yagami’s downfall, she evades Teru Mikami’s assassination attempt via a forged Death Note. Post-Kira, she remains allied with Near, Anthony Rester, and Stephen Gevanni in ongoing investigative work. Adaptations outside the manga, such as the anime, streamline her story—omitting moments like her sheltering Mello or using shower conversations to evade surveillance—reflecting narrative adjustments in condensed or reinterpreted versions of the plot.