The Dii h'anno Doors was a temporal gateway to Hyspero, located inside of one of the New Gods. The space in between the Dii h'anno Doors and Hyspero resembled a long corridor, with strange images on the walls.
Anthony Marvelle and Missy, with a kidnapped Kelly in tow, used the Dii h'anno Doors to reach Hyspero, so Marvelle could complete his plans. Jenny, Euphemia, and Barbra also used the Dii h'anno Doors minutes after Marvelle had. (PROSE: Enter Wildthyme)