The Dragon Quest series might seem as if it follows the example set by Final Fantasy and uses self-contained storylines and worlds for each of its games, but that is not the case. The first six Dragon Quest games are actually two separate trilogies, with the first three games being known as the "Erdrick" trilogy and the other three games are called the "Zenithia" trilogy. The Erdrick trilogy is named after an important hero and his descendants who star in each entry in the original trilogy, while the Zenithia trilogy is named after a floating city that appears in Dragon Quest IV: Chapters of the Chosen, Dragon Quest V: Hand of the Heavenly Bride, and Dragon Quest VI: Realms of Reverie.
The first three games in the Dragon Quest series were trailblazers for the JRPG genre and they helped cement the franchise as a national treasure in Japan. The original trilogy might seem primitive by today's standards, but they set the standards for the genre as a whole.
Erdrick's name was originally localized as Loto outside of Japan, as it's closer to the original Japanese version of the word. The term Loto is now only used to refer to the early localizations of the Dragon Quest series where it was used and Erdrick is considered to be the correct term and is used in the current games. The Erdrick trilogy takes place outside of a regular continuity order, as Dragon Quest III: Seeds of Salvation is actually a prequel to Dragon Quest, which is followed by Dragon Quest II: Luminaries of the Legendary Line.
Dragon Quest III: Seeds Of Salvation
The term Erdrick actually refers to a title that is given to a legendary hero, rather than being an individual name. The player isn't actually allowed to name their character Erdrick/Loto in order to preserve the twist regarding the name at the end of the game.
The main character in Dragon Quest III: Seeds of Salvation is the son or daughter of a famous hero named Ortega, who perished fighting a demon lord known as Baramos. The protagonist forms a party of adventurers and goes on a quest to slay Baramos. The story involves the party traveling to a land known as the Dark World and defeating an even more powerful demon known as Zoma.
The connection between Dragon Quest III: Seeds of Salvation and the other games in the series is revealed gradually over the course of the game. The Dark World is actually Alefgard, the main location of the original Dragon Quest, which is restored to prominence over the course of the game. The protagonist is given the title of Erdrick at the end of the game, signifying them as the legendary hero from the backstory of Dragon Quest.
The hero from the original Dragon Quest is a descendant of Erdrick, who is referred to as a great hero from the past.
The hero must defeat a creature known as the Dragonlord, who has stolen both the Ball of Light and Princess Lora of Tantegel Castle. In order to follow the Dragonlord to his stronghold, the hero must travel to Erdrick's tomb and seek out a tablet that contains a message written by his ancestor. Erdrick's message states that he needed the aid of three items in order to be able to continue his journey and that he left them with three wise men of the kingdom, whose descendants will pass them on if the hero proves himself to be worthy.
The story of Dragon Quest ends when the hero slays the Dragonlord and saves Princess Lora. The two of them would later marry and their descendants would form three different kingdoms.
Dragon Quest II: Luminaries Of The Legendary Line
Dragon Quest II: Luminaries of the Legendary Line tells the story of the descendants of Erdrick and the hero from the original Dragon Quest. The game takes place a century after the events of Dragon Quest, with the main character being the Prince of Midenhall, who is spurred to action when an evil wizard known as Hargon destroys the kingdom of Moonbrooke.
The Prince of Midenhall does not have to be alone on his journey, as he can team up with two of his cousins, who are also descendants of Erdrick. The other party members are the Prince of Cannock and the Princess of Moonbrooke, both of whom are powerful spellcasters.
The story of the Erdrick trilogy ends when the party defeats both Hargon and his demonic master, Malroth. The party finally manages to bring true peace to the land after centuries of conflict with the forces of evil.