Iczel is a sentient robotic entity engineered by the advanced alien Iczers to merge with human partners, forming symbiotic combat units called Iczelions. Tasked with defending planets from destructive machine life forms spawned by Big Gold, a recurring antagonist in the franchise, it bonds with hosts to transform into powered armor, amplifying their physical and tactical capabilities. This system serves as a scalable defense strategy, replacing direct interventions by Iczers like Iczer-3, who dispatches Iczel to Earth in an alternate timeline.

Its chosen partner, Nagisa Kai, is a high school student training to become a professional wrestler. Though initially hesitant, Nagisa synchronizes with Iczel to unlock combat enhancements, their partnership marked by clashes over strategy—Nagisa favors wrestling-inspired close-quarters tactics, while Iczel prioritizes efficient beam attacks. Successful synchronization hinges on emotional and mental alignment, emphasizing the conquest of fear rather than resolving past traumas.

Multiple Iczel units operate on Earth, each color-coded and paired with distinct partners. Classified as the "Normal Type," Iczel employs defensive barriers as its primary weapon, contrasting with variants specializing in gravity manipulation or elemental assaults. These units adapt personalities reflecting their human counterparts, though Iczel maintains its core analytical demeanor.

A supplemental radio drama anchors Iczelion’s lore within the broader franchise, linking it to Iczer-3’s timeline and introducing Nagisa Kasumi, a prior Iczerion partner from that continuity. While the animated OVA and radio drama establish these connections, unresolved narrative threads and the series’ limited two-episode run leave Nagisa Kasumi’s relationship to Iczel and broader conflicts unexplored in subsequent media.