Daisuke Jigen stands as a highly skilled marksman and Lupin III's long-time partner, defined by loyalty and pragmatism. In "Goodbye Partner," external coercion forces his apparent betrayal, not genuine intent. Antagonists threaten Alisa Cartwright, a young pianist connected to Jigen's past, leveraging her safety to compel him against Lupin despite their deep trust.

His backstory with Alisa's mother, Riley, underpins this protectiveness. Years prior, Jigen ended their relationship, convinced his life offered no stability, stating, "All I can do is shoot a gun." Though he promised Riley aid if danger arose, he couldn't prevent her death. This unresolved guilt drives his fierce determination to safeguard Alisa, seeing it as a final obligation to Riley.

Alisa draws out rare emotional vulnerability from Jigen. He displays uncharacteristic protectiveness, attempting to soothe her distress with small gestures like Lupin’s flag trick—his inherent awkwardness contrasting sharply with Lupin’s effortless charm. When Alisa is kidnapped, Jigen prioritizes her rescue over his partnership, leading to a high-stakes clash with her captors.

Jigen's legendary gunman skills remain central. His 0.3-second quick-draw and firearm precision are consistently demonstrated, including reassembling his signature Smith & Wesson Model 19 revolver under pressure. The climax sees him deploy an experimental railgun to breach a fortified enemy stronghold, showcasing tactical ingenuity and combat mastery.

Reconciliation with Lupin and Goemon Ishikawa XIII follows Alisa’s rescue. Both immediately recognize the coercion behind Jigen’s actions, dismissing his guilt with characteristic nonchalance—Lupin offering instant forgiveness and Goemon responding with dry humor. This reaffirms their unbreakable bond and Jigen's seamless reinstatement within the group.