Swing Out Sisters (2014)

Living under the same roof as two very different older sisters is something Yuuta can't escape — Chiyo, the soft-spoken, nurturing one who basically treats him like her whole world, and Chinatsu, the tomboyish firecracker who expresses affection through relentless teasing and picking fights. As Yuuta tries to buckle down and study for exams, both sisters start pulling him in completely different directions, each wanting his attention in her own way. What starts as familiar sibling banter gradually shifts into something more complicated and charged, and the household dynamic gets harder to ignore. The two sisters couldn't be more different from each other — Chiyo is warm and openly affectionate, while Chinatsu is competitive and guarded about her feelings — and watching those contrasting personalities collide over the same guy gives the OVA most of its energy. The animation from Tryforce is clean and expressive, and the character designs do a solid job selling how distinct the two sisters actually are as people, not just archetypes. It's a single-episode OVA, so it moves fast and keeps things focused on that central dynamic rather than stretching things out. If you've watched Kiss x Sis or Yosuga no Sora and appreciated how those handled complicated sibling-adjacent relationships with some genuine emotional tension alongside the fan service, this sits comfortably in that same space. Oniichan no Koto Nanka Zenzen Suki Janain Dakara ne is another fair comparison if you liked the tsundere sister angle specifically. Short, contained, and pretty straightforward about what it is.