Koizumi Isuka
小泉 イスカ
| Koizumi Isuka小泉 イスカA | |
| Measurements | Bust-Waist-Hips: 65-52-72cm, AA cup |
| Birthday | 16 February |
| Hair | Black, Multicolored, Red, Shaggy, Side Tail, Waist Length+ |
| Eyes | Amber |
| Body | Pale, Slim, Teen |
| Clothes | Belt, Hairpin, Knee-high Boots, Miniskirt, Pleated Skirt, Scarf, Tank Top, Thigh-high Stockings |
| Items | Fanny Pack |
| Personality | Airhead, Clumsy, Honest, Lazy, Sweets Lover |
| Role | Ninja, Thief |
| Visual novels | Main character - Grisaia: Chronos Rebellion |
| Voiced by | Ogura Yui |