Nina’s primary romantic storyline revolves around her feelings for Mikazuki (Mika). This relationship defines her character arc and is a major talking point for fans of the series.

The Setup: Unlike the other girls in Tekkadan who viewed Mika as a terrifying weapon or a distant leader, Nina saw him as a human being. She was one of the first people to treat him with casual kindness, offering him food and engaging him in normal conversation. This established her as the "safe harbor" for Mika—someone he could relax around.

The Dynamic: Throughout Season 1 and early Season 2, the show builds a quiet romantic tension. Mika is comfortable with Nina in a way he isn't with others (even his official "partner" Kudelia, at first). There are several key scenes where Mika initiates physical closeness with Nina (like sleeping on her lap or holding her hand), which fans interpreted as him finding emotional grounding in her.

The "Missed Connection": The tragedy of Nina’s romantic storyline is that it is defined by silence. While she harbored deep feelings for Mika, she recognized that his world was one of constant violence and that his destiny was intertwined with Orga Itsuka. She loved him, but she also understood that she couldn't follow him into the battlefield.

The Tragic Resolution: Ultimately, Mika’s romantic choice (or rather, his commitment to survival and protecting those close to him) leaned toward Kudelia and Atra. Nina becomes the "tragic observer." She confesses her feelings to Atra in a moment of vulnerability, admitting she is jealous but accepting of her place. Her storyline ends not with a romance, but with the grief of losing Mika and the responsibility of helping raise his child with Kudelia and Atra.

Here is where we must tread carefully. K-pop fans often struggle to separate the idol from the character.

Nishimura Nina (the real person) is famously private. She rarely posts selcas with male idols. She doesn’t do the usual "skinship" fanservice with her members that other groups rely on.

However, Nina (the IM character) is a mess of yearning and intensity.

In KATSEYE’s variety content (e.g., Katseye: Backstage or fan-meeting skits), Nina is often paired with specific members to reenact romantic scenarios. For example, in a Halloween special, Nina and a fellow member performed a parody of a K-drama proposal. This is not real; it is a romantic storyline designed to make fans laugh and clip the moment for TikTok.

Another compelling dynamic was between Nina and Swiss-Ghanaian member Manon Bannerman. Because Nina struggled with Korean at the time, she often defaulted to English, connecting deeply with the English-speaking trainees. Editors played up moments of Nina and Manon whispering to each other during rehearsals, creating a "us against the world" storyline.

The Romantic Storyline: This ship leans into the "opposites attract" trope—Nina’s disciplined, perfectionist nature versus Manon’s ethereal, free-spirited vibe. However, this is strictly a fan-constructed narrative; no evidence suggests a romantic connection.