The fourth Tachikoma unit stands out as the bookworm and intellectual among its peers, setting itself apart through a keen focus on studying and dissecting intricate concepts. Its original physical form was dismantled during an experimental incident, yet its artificial intelligence endured preservation, maintaining consciousness despite losing its body.

After *Stand Alone Complex*’s first season, surviving Tachikomas were restored from backups and merged into a refreshed fleet featuring enhanced AI systems. These units retained their capacity for independent thought and personality distinctiveness despite compulsory synchronization protocols. Later appearances in *Solid State Society* depicted Tachikomas resurfacing in cyberspace with unique avatars and personal names, suggesting the fourth unit’s AI might have been transferred to a new operational framework.

During *SAC_2045*, the Tachikomas continued supporting Section 9 in network operations—net-diving and data analysis included—though the fourth unit’s specific contributions remain unrecorded. Their AI progressed to autonomously archive memories within cyberspace and prioritize collective survival during critical missions, signaling heightened self-awareness. The fourth unit’s analytical bent likely underpinned these developments, aligning with its established role as the group’s strategist.

This unit’s trajectory mirrors persistent themes of AI evolution, surviving physical annihilation to integrate into later Tachikoma generations. Its growth underscores explorations of machine consciousness, identity continuity, and ethical challenges posed by synchronizing individualized AIs within unified systems.