The appearance of the trophies follow the release of Dragon Quest XI: Echoes of an Elusive Age for PlayStation 4 and 3DS in Japan on July 29.
Update 08/01/17 at 11:20 a.m.: It has been revealed that the original Dragon Quest is a bonus for users who clear Dragon Quest XI: Echoes of an Elusive Age.
To obtain the original Dragon Quest on either PlayStation 4 or 3DS, the player simply needs to enter the “Spell of Restoration” that appears in the credits after the true ending. Doing so will enable the player to download the original Dragon Quest.
Thanks, Hachima Kikou.