Cult Classic: Dragon Quest, despite being the seminal JRPGs, wasn't really able to gain a foothold in America during the 90s. It fared much better during the revival in the oughties, but not enough to convince Square Enix to continue localizing much past IX and the remake of VI, which were only even released outside Japan because Nintendo put in the effort to. It wouldn't be until Heroes that Square Enix started localizing the games again, and some of them such as the remakes of VII and VIII only happened thanks to Nintendo once again handling publishing duties.
Demonic Spiders: Lots of examples, particularly enemies that are immune to magic, can One-Hit Kill you, cast Sleep, Healmore/Midheal, and/or Hurtmore/Firebane/Sizzle (Wizards), inflict poison or other Status Effects, and have high defense or speed stats (which makes them dodge and block you a lot, eg Demon Knights).
Fan Nickname: In Japan, the heroes of each game are referred to as the number of the game they appeared in (the hero of Dragon Quest IV is called Four, the hero of Dragon Quest VIII is called Eight, etc.); the exceptions are the hero of Dragon Quest III is called either Erdrick or Three and the heroes of Dragon Quest II since there are 3 heroes in that game.
Germans Love David Hasselhoff: The biggest fanbase in the Western Dragon Quest community appears to be in France, as it was the French fanbase that ultimately got Square Enix to release the 3DS remake of Dragon Quest VII worldwide.
Across the games there's the recurring masked muscleman/thug NPC model, which can be described as a bodybuilder in a body harness and a horned hood mask.
The epic victory music when a new character joins your party.
For anybody in Japan, as well as Western Fans who wait deperately for new games to be localized, just hearing the series theme song is enough to get the blood flowing.
The various sounds throughout the series for when you get a Critical Hit. At least when you're not on the receiving end of one.
The jingle that plays every time you win a battle. Virtually unchanged since its debut in 1986, and it's as memorable as ever.
Dragon Quest V features monster catching and predated Pokémon by a good three years. However it's pretty undeniable that the Dragon Quest Monsters series was created due to Pokémon.
The concept of Psyching characters up to deal more damage actually started in Dragon Quest VII, but it was only used via special moves, and there was only 1 level of tension. Dragon Quest VIII greatly expanded on the idea and Tension because a core part of all Dragon Quest games, including spin-offs, until being supplanted by the Pep system in DQXI.
Overshadowed by Controversy: In countries with contentious disputes with Japan over World War II, such as China and South Korea, it is hard to talk about the series without going into the political views of composer Koichi Sugiyama, a conservative nationalist who openly denied the Nanjing Massacre and Comfort Women.
Pop Culture Holiday: An unusual case where the holiday changes with its observance. Dragon Quest games are known for releasing on Saturdays, so when a new installment comes out, playing and talking about Dragon Quest is made into a weekend event.
Porting Disaster: The general opinion of the mobile ports of the first three games. A lot of the monster sprites are Off-Model or lazily put together, the tile work is rather grating to look at, and the most of the problems with the games from the original are still present. The fact the Nintendo Switch ports were based on these versions instead of the more acclaimed SNES remakes upset many fans.
That One Attack: Whack spells, in all the games they appear in. Spells that are reliant on RNG in general get this due to the enemy AI abusing it, but Whack spells are especially dreaded because they can instantly kill party members in a series where revival spells are also dependent on RNG luck. If you're especially unlucky, you might end up wasting turns trying to revive your party members while there's an enemy casting Whack (or worse, its deadlier version Thwack) spells again and again.
Woolseyism: The games released since Dragon Quest 8 have actually been blessed with a remarkably coherent localization, but contrary to popular belief the Hurricane of Puns, Added Alliterative Appeal, and general silliness of the franchise are actually taken from the Japanese originals (though sometimes rather heavily re-contextualized in service of trying to make the experience cohesive in the new language, the end result of which can be hit or miss, sometimes, depending on the player).
, a conservative nationalist who openly denied the Nanjing Massacre and Comfort Women.