OVA
Description
Kasuga hails from Sasuke Sarutobi's ninja village, initially sharing a sibling-like bond with him. Sent to assassinate Kenshin Uesugi, she instantly fell in love upon meeting them and abandoned her mission. This failure resulted in her exile from the village. She subsequently joined the Uesugi clan, becoming Kenshin's most loyal ninja. Sasuke later observed that serving Kenshin enabled Kasuga to "become human" again by rediscovering emotions like love, contrasting his own path.

Her devotion to Kenshin manifests absolutely, often triggering intense physical reactions to their praise or attention: trembling, moaning, and entering euphoric states where she clutches herself while whispering Kenshin's name. These episodes occur during missions or private moments, sometimes noticed by others. Despite this, she maintains professionalism, displaying cold efficiency as a strategist and battlefield operative when focused. She exhibits warmth towards Uesugi allies and rarely kills unless necessary to protect Kenshin or their vision.

Kasuga sustains specific rivalries:
- Her history with Sasuke involves frequent clashes over ninja techniques and ideological differences, though underlying camaraderie persists. She reacts with irritation to his teasing but accepts his help when goals align.
- She views Nōhime as a counterpart due to their similar roles as protectors and confidantes to powerful warlords, fostering a professional rivalry.

In combat, she initially wielded dark energy-imbued ring blades in *Sengoku Basara*, later adopting kunai connected by razor wires for binding enemies. Her abilities include light-based techniques: Solar Eclipse for stunning foes and Sunspot for teleportation counters. She also utilizes an owl familiar for gliding and reconnaissance.

Her appearance features short blonde hair with long side tails, yellow eyes, and a distinctive low-cut bodysuit noted for its suggestive design, which embarrasses her.

Across media, Kasuga's role fluctuates:
- She appears as a playable character in *Sengoku Basara* and *2*, transitions to NPC status in *Sengoku Basara 3*, and returns as playable in *Sengoku Basara 3 Utage* and *4 Sumeragi*.
- In the anime, she takes bullets defending Kenshin, triggering a distraught scream, and later survives a sword injury during a rescue attempt in *Sengoku Basara 4 Sumeragi*.
- The film *Sengoku Basara: The Last Party* briefly features her unconscious after a battle.