Deana del Rio is the primary sniper for special investigations unit Seven-O, identified by her signature pink designation. She operates independently, often disregarding procedures during casework, which causes frequent friction with her strictly-by-the-book partner, Katherine Roshfall. Their clashing methods create tension but establish a consistent Good Cop/Bad Cop dynamic in interrogations and field operations, contrasting Deana's aggressive tactics with Katherine's measured approach.

Deana sports long, girlish pigtails reaching halfway down her back. Her personality is blunt and occasionally rude, prioritizing results over protocol. She adopts the unit's nickname tradition, calling Kirill Vrubel "Kariage" (Buzz-cut) and Katherine Roshfall "Kay", despite her own initial resistance to such informality. Her conduct includes leveraging sensitive personal information for amusement, such as enforcing secrecy around Valery Vrubel's gender identity solely because she found the situation entertaining.

Professionally, Deana contributes to operations targeting law enforcement corruption, including assisting in the arrest of narcotics detective Gary for attempting to steal and sell Seven-O's specialized anti-Anthem ammunition. Her role remains focused on field operations and marksmanship across documented missions, without significant evolution in responsibilities or interpersonal dynamics beyond established patterns.