Shiki Seiichi manga
Takes place approximately 50 years after the original D.C. ～Da Capo～ series. The story revolves around Sakurai Yoshiyuki and Otome & Yume, the two granddaughters of the original D.C. ～Da Capo～ protagonists Junichi and Nemu. "This is actually the second manga based on Da Capo II in active serialization. The other manga, running in Kadokawa’s Comptiq magazine, is considered to be the “canon” adaptation of the story (i.e. it’s based directly on the game). As the title “Imaginary Future” suggests, this manga proposes an alternate deviation from the game’s premise, where fan-favourite Nanaka Shirakawa (speculated to be a descendant of the famous Kotori Shirakawa) is the story’s main heroine."
From Kirei Cake: Aisupe @ is a love comedy story based on the online game "ai sp@ce" that features cosplaying using various heroines from popular games and shows such as D.C. II, CLANNAD, and SHUFFLE! as references!