Steela attends Destiny Land Academy in the underworld, marked by her distinct noseless face and perpetual frown, lending her an emotionless air. Her stitched desk subtly hints at her narrative importance. Initially feared and despised by classmates who perceive her as taciturn and gloomy, she remains isolated due to her unsettling presence.

Her heritage binds her to the series' mythology; she is the daughter of Cain, reinterpreted as the demonic Headmaster Hellvis. This lineage ties her to the conflict over Hell's origins, a self-inflicted construct fueled by Abel's (Ryu Kutou) grudge against humanity. Steela possesses the hidden power "Cessation of Existence," enabling her to erase souls within Hell, a pivotal ability in the climax.

Steela's development ignites through her bond with protagonist Rinne Amagane. Rinne's persistent kindness—the first she'd known—triggered a shift, fostering fierce loyalty and protective instincts. This motivates Steela to repeatedly intervene for Rinne, including against Ryu Kutou's efforts to block their escape from Hell. Her emotional evolution culminates in a rare smile following Rinne's volleyball tournament victory, symbolizing her internal change.

The narrative concludes with Rinne returning to the living world but losing all memories of Hell and Steela. In a poignant moment, Rinne inadvertently names a rescued girl "Steela," implying a subconscious connection. The story suggests Steela may now watch silently over Rinne from afar as gratitude for their friendship.