Producer Yuji Naka stated in an interview with IGN that eggs were chosen as the focus of the game to give the player joy from caring for and hatching eggs, and a feeling of anticipation "because you don't know what's going to come out of eggs".
The Dreamcast version of Ephemeral Fantasia was to feature cameos by Sega characters including Sonic the Hedgehog, Ulala, Ryo Hazuki, and, oddly enough, notable Sega developers Yu Suzuki and Yuji Naka.
While creating concept art for the game, Sakai drew a dragon and showed it to Yuji Naka, the director of Sonic Team, who connected the image with the Phantasy Star series of games that had been released for the Sega Genesis.
Yuji Naka had limited involvement in the development of Sonic Advance 3, and conceived of the two-player dynamic.
Yuji Naka | Yuji Nagata | Yūji Tajiri | Yuji Ijiri | Yūji Aoki | Yuji Yoshino | Yuji Yoshimura | Yūji Tsushima | Yūji Kishi | Yuji Hamano | Yuji | Nāka | Naka | Harukanaru Toki no Naka De | Harukanaru Toki no Naka de |