"Dragon Quest Monsters (ドラゴンクエストモンスターズ Doragon Kuesuto Monsutāzu) or Dragon Warrior Monsters, as it was known in North America, is a spin off series of the Dragon Quest games. Published by Enix Corporation (now known as Square Enix), it sets the player in a medieval/fantasy world filled with magic, monsters and knights. Unlike the original Dragon Quest games, the player's character doesn't do any of the fighting in battles; instead the player has to rely on capturing, breeding and raising monsters to do the fighting for them. The concept originated from Dragon Quest V (1992). The character and monster designs are by Dragon Ball creator, Akira Toriyama. The series spans several handheld gaming systems and each game has received positive reviews from critics. Upon the series' debut in the US, it was quickly labeled as a "Pokémon clone" by critics.
For the first two US releases, the titles used Warrior instead of the original Japanese Quest. This was due to Dragon Quest's North American name being changed due to a trademark conflict with the role-playing game DragonQuest, which was published by Simulations Publications in the 1980s until the company's bankruptcy in 1982 and purchase by TSR, Inc., which then published it as an alternate line to Dungeons & Dragons until 1987. In 2003, Square Enix registered the Dragon Quest trademark in the US, making the Dragon Warrior name obsolete."
Source: Wikipedia, "Dragon_Quest_Monsters", available under the CC-BY-SA License.