石馬戒厳 (Ishima Kaigen) is an eighty-two year old soldier who appears in the eroge "Hanachirasu" made by Nitro+ (NitroPlus). Ishima has the appearance of a small girl with long, black hair, wearing an Imperial Japanese Army uniform and she fights with a katana.
Ishima is a parody of Katou Yasunori , appearing as an antagonist in Aramata Hiroshi 's Teito Monogatari .
The voice actress for Ishima is Hokuto Minami , a very famous eroge voice actress.
Ishima Kaigen appeared later in the Nitro+ 2-D fighting game called "Nitro+Royale: Heroines Duel". At Ishima's end of the game, or rather her ending itself, is a seiyuu joke.