H2O: Footprints in the Sand is a Japanese adult visual novel by Makura that was released on June 23, 2006 for Windows as a DVD; a version playable on the PlayStation 2 under the title H2O + followed on April 24, 2008 with adult content removed and added scenarios and graphics not seen in the original release. H2O is Makura's first game; a sequel named Root After and Another was later produced in October 2007. The gameplay in H2O follows a plot line that offers pre-determined scenarios with courses of interaction, and focuses on the appeal of the three female main characters. There are two modes of gameplay, the Blindness Effect and Normal Effect, where the former plays on the fact that the protagonist is blind, and the latter mode removes the added element of gameplay the Blindness Effect has. The story is broken into three parts: the original introduction and meeting, following by a separation and reunion, and finally ending with the protagonist choosing one of the girls and spending the rest of the game with her.

Ami Koshimizu is a Japanese actress and singer. She has voiced many different types of characters, from young girls to adult women, as well as boys and animals. Her roles include leads such as Ryuko Matoi in Kill la Kill, Kallen Stadtfeld in Code Geass, Nadja Applefield in Ashita no Nadja, Leonmitchelli Galette Des Rois in Dog Days, Yumi Hoshino in KimiKiss: Pure Rouge, Takuto Hasegawa in Magician's Academy, Hibiki Hojo in Suite PreCure, Nanaka Yatsushiro in Myself ; Yourself, Himari Noihara in Omamori Himari, Sailor Jupiter in Sailor Moon Crystal, Mikumo Guynemer in Macross Delta, Nodoka Haramura in Saki, Tenma Tsukamoto in School Rumble, Holo in Spice and Wolf, and Yang Xiao Long in both RWBY and RWBY: Ice Queendom. In video games, she voiced notable characters like Agnès Oblige in Bravely Default, Mai Shiranui since KOF Sky Stage, Mist in Rune Factory, Rimurisu in Tears to Tiara, Rinka in the Atelier series, Miyabi in Zenless Zone Zero, Rosa Ushiromiya in Umineko: Golden Fantasia, Tsuruhime in Sengoku Basara, Yukiko Amagi in Persona 4, Beidou in Genshin Impact, and Zima and Projekt Red in Arknights. She also is known for her dubbing role for Thailand films which starred Yanin Vismitananda. In addition, she also voiced in the live action anime film Shimajiro and the Rainbow Oasis.