It's not a very good idea to start an argument over which game in the series is the best, and that includes Bloodborne and Demon's Souls (and maybe Sekiro: Shadows Die Twice). All 3 games (5-6 counting the "unofficial" entries) have their supporters, and arguments between them can get quite heated.
The Invasion PvP mechanic is also a common source of contention. It takes a few different forms, but many of them involve other players forcing their way into others' worlds without their consent for the purpose of killing them and hindering their progress. Several game mechanics actively reward this behavior, from offering useful items to advancing in various covenants. There are existing ways to play around it, mostly involving not invoking a powered-up state without which you cannot be invaded or playing offline, but such players cannot then summon either NPC allies or other players to help them either, and in the latter case don't enjoy messages and encouragement from other players. This is commonly regarded as actively rewarding griefing, especially since some forms of it actively encourage high-level players to attack lower-level players. There are even a few people who are aware of this mechanic in Dark Souls and refuse to play the series because of it. Those who do it tend to be very, very defensive, though.
Which is better: strength builds or dexterity builds? Strength weapons swing more slowly, and necessitate equipping the heaviest armor possible to maximize poise to continue their attacks uninterrupted, but as a result have weapons that deal the highest damage and make stun locking easier with their poise damage. Defenders of dexterity point out that this limits the variety of weapons, rings, and armor players can equip, and that it's more important to maximize your ability to dodge in order to escape stun locks, and a flurry of weaker attacks can have the same results as a good strength weapon. The slow nature of strength weapons means a single misstep can result in disaster; strength defenders argue this simply makes strength Difficult, but Awesome. This divide only got deeper as more games were released, and every subsequent game nerfed poisenote In DS1, poise was constantly active; in DS2 poise was only active while you were performing an action, and in DS3 it was only active during certain frames of specific actions, making it seem like the developers favored dexterity over strength.
Players dedicated to PvP in the level 120 "meta" range will usually rely on the so-called "quality build" (40 to 50 Vitality, 30-40 Endurance, 40 Strength and 40 Dexterity) and rely on the top few weapons (of the many viable weapons) that best match those builds. As a result, PvP has little variance. note Dark Souls II ups the PvP meta level range a little at 150, but has the same gist.
A common trend among builds with enough Strength and Vitality is towards the use of a One-Handed Zweihänder, whether it be pairing it with a shield, or dual wielding them.
Difficulty Spike: Even given that the games are tough as nails, there are usually bits where it goes from "very hard" to "much harder than that": Blighttown in the first game, for example, is like having all your teeth pulled out by a dentist with very dirty hands, while the Cathedral of the Deep in the third starts off a sequence of 4-6 That One Levelsin a row.
An odd mix of this and Friendly Fandoms with The Legend of Zelda, particularly around the divisive Wii/DS years of the latter series. With many longtime Zelda fans being disillusioned with the series for moving towards linearity, greater focus on story, and lowered difficulty, many of them came to Dark Souls for an more open experience with little handholding, a more subtle and mysterious story, more complex and difficult combat. As such, it isn't uncommon for many classic Zelda fans to name Dark Souls as "what Zelda should be." With the release of Breath of the Wild managing to Win Back the Crowd for these fans, many of them credit Dark Souls for inspiring Zelda to "return to its roots."
A straight example of this is with The Elder Scrolls. As both Dark Souls and Elder Scrolls are two of the most popular Action RPG franchises of The New '10s, fans of both tend to clash with one another.
Developed one for a while with the Monster Hunter community after the Monster Hunter: World reveal, with many a Souls fan making comparisons. Veteran Monster Hunters were not amused; While it isn't the only game to be compared due to difficulties, the former were most vocal. It was mostly one-sided, as most Souls players enjoyed the latter.
Fandom VIP: The Dark Souls community has several: VaatiVidya and Epic Name Bro are both known for their in-depth, comprehensive analysis of the game series' lore (which is famously vague and complex). OnlyAfro, on the other hand, is a Fountain of Memes who usually posts videos of himself trolling people in PvP in numerous inventive (and usually hilarious) ways.
First Installment Wins: While there are vocal contingents who prefer the two sequels, the first Dark Souls tends to be more well-loved and less controversial than either of its sequels, which endlessly get compared to the original because of this. Some of the more extreme fans consider the "real" Souls series to be Demon's Souls, Dark Souls, and Bloodborne (with Sekiro sometimes thrown in), feeling that From is at its best trying to build new franchises with somewhat similar, yet ultimately distinct design philosophies and gameplay over attempting to build on what was already good.
With Berserk, due to the huge influence the manga has had on Dark Souls, whose developers are fans of the series. Some fans go so far as to consider Dark Souls a better adaptation of Berserk than the actualvideo games based on the series.
The fans are also quite friendly to Re:Zero, because the anime adaptation of the latter was found as a fairly interesting Spiritual Adaptation of the series with its idea of returning back after death.
Game-Breaker: There are many, many ways to heavily mitigate the difficulty of each game in the series, as explained on this page. That said, most of them don't work in every situation, and From often patches out the more egregious ones.
Genre Turning Point: Prior to the first game, third-person action games generally consisted of button-mashing until one defeated their enemies, with success in battle usually determined just by making effective use of special moves and not trying to take on too many enemies at once (and having the right armor and weapons, if the game had any sort of equipment system). Dark Souls, while not the first game to place an emphasis on learning enemy attack patterns and then effectively countering and dodging them while also eschewing any form of Mercy Invincibility, thus allowing enemies to quickly stun-lock and beat you to death if you tried button-mashing your way to victory was the one which made it the standard approach for action games in The New '10s.
Germans Love David Hasselhoff: The games are successful in Japan, but find their largest audience in Europe and North America, largely because they're strongly Western in terms of gameplay and aesthetics.
Hype Backlash: Some feel that the series' memetic status as the gold standard for Nintendo Hard modern video games ("_____ is like Dark Souls!" "The Dark Souls of _____") has gotten worn out over time. Most of these complaints come from players who have gotten used to the series' brand of challenge, as well as fans of other challenging games. This phrasing has also been used unironically by multiple game reviewers to a great deal of mockery, such as Gamesradar and Eurogamer with Crash Bandicoot N. Sane Trilogy and Spyro Reignited Trilogy respectively claiming that the games are "too hard".
Memetic Badass: Plenty within the actual games, but the series itself has become a bizarre meta example. Just about any game that's even moderately challenging will be compared to Dark Souls or be called "the Dark Souls of its genre", even games with absolutely no similarities to the series, such as Cuphead.
Another meta example is VaatiVidya, a youtuber who does lore summaries on the characters and stories of the games. His videos are usually the average player's first introduction to the deep lore of the series, which has garnered him fame as the prime expert on the subject. Especially since he's able to ramble of the insanely intricate lore at a moment's notice.
Misaimed Fandom: No, you're not supposed to have any sympathy for people who invade as a red. Problem is, players who set themselves up with others to "gank" are seen in the wrong.
Gwyndolin is a popular character among transgender players thanks to said fans sympathising with how he's forced to pretend to be a woman, but a certain aggressive minority of these fans instead read Gwyndolin as being a transwoman, completely disregarding all of the evidence in the game that says otherwise and even verbally attacking fans who refer to him with male pronouns while steadfastly referring to him with female pronouns. In other words, doing the very same things that in the lore of the game made Gwyndolin miserable.
Most Wonderful Sound: The ambient hum that is heard whenever you enter a new location or light a bonfire. In the latter's case, this is exceptionally soothing to hear after going through That One Level and finding a bonfire right afterwards.
Play the Game, Skip the Story: While the trilogy does have a complex story, many chose to play through the game instead since the story is not something that's outright told, most of it being in the item descriptions, the big draw mostly being the challenging gameplay.
Popular with Furries: Despite the game series being a depressing Dark Fantasy, it still gets its own fair share of furry fans, with prominent examples being the Bell Gargoyles, Capra Demons, and especially the Dragonoidforms. Said Dragonoids are especially prone to receiving Self-Fanservice from furry artists, most notably Dark Souls III's incarnation.
The Company of Champions in the second game is explicitly built to be this. After the (many) warnings the game presents you with, joining the associated covenant will give enemies boosted damage and health, infinite respawns, and will disable co-op until you abandon it.
"Castlevania/Belmont Runs" a.k.a. Whip-only runs (which the game admits flat out on the weapons description is a Joke Weapon almost useless against anything with armor) are common. Less ridiculous in the second game, where whips become a Lethal Joke Item on Dexterity builds if you can keep your foes at a distance.
The famed "Guts Run", meant to emulate the main character of Berserk (no helmet, no shield, only two-hand melee weapons, only crossbows as ranged weapons, no spells outside of ranged fire spells, throwing knives and emergency dagger allowed).
Similar to the "Guts Run", is the Cosplay Run. Essentially you do your best to look like a character from another piece of media and try to emulate their fighting style, appearance, and personality as best as possible.
More generally, there's the "Fashion Souls" style. The idea is to get good enough at the game that you can ignore stats entirely and just wear whatever looks cool or silly to you.
The Soul Level 1 run, which is completing the entire game without ever leveling up.
Sidetracked by the Gold Saucer: Even before the actual gameplay! Due to armor stats only serving a purpose in extreme cases, people tend to make various cosplay builds, but spend a good deal in the complex character creation.
Unconventional Learning Experience: Dark Souls teaches you different types of medieval weapons and armors (standard weapons, not boss weapons) as well as bringing attention to historical European martial arts (HEMA). That said, the overswings may get you killed in a real fight.