- Solaire of Astora, patron saint of Jolly Cooperation, the usually upbeat, friendly, kind and helpful knight who you can summon to help with multiple bosses, including, if you've gotten enough ranks in the right covenant, the Final Boss. The Warrior of Sunlight covenant that he represents is the only one to appear, essentially unchanged, in all three games, and Solaire himself has become essentially a Series Mascot, even being the first character from the series to get an Amiibo!
Is that the Praise the Sun guy? I feel like I've just seen a celebrity.
- Siegmeyer of Catarina, who's second only to Solaire in friendliness, as well as being a fun, goofy guy in a suit of armour that looks like an onion.
- Everything to do with Knight Artorias. Artorias himself is an agile knight in distinctive, badass-looking armour, whose distinctive, ornate and extremely large greatsword pops up across the series. There's also his pet, the game's most noble puppy, Great Grey Wolf Sif.
- Ornstein and Smough are a mid game boss that grew to be Series Mascots in their own right, representing the bosses like Solaire represents the characters. They are generally considered to be the best Boss fight in the game, and ranked high on lists of the best boss fights in gaming. When you see a list of Dark Souls bosses, expect Ornstein and Smough to be the page image.
- Crossbreed Priscilla, being the only boss that won't attack you on sight and asks you to leave her alone. Her sad existence and being a Cute Monster Girl means players are inclined to spare her. It's a common meme to suggest the Chosen Undead just take all the friendly NPCs and transfer them to the Painted World and hang out with her.
- Lucatiel of Mirrah has a truly tragic story in a series that's not short on depressing character arcs. The fact that she's a badass female knight with a snappy Spanish-influenced visual design who can hold her own when summoned helped cement her as the most popular NPC in the game. Her impact was noticeable enough that her full set appears in Dark Souls III, and her mask specifically highlights that her name was remembered, in accordance with her wishes.
- Vengarl of Forossa became popular through his unique nature: he's an extremely mellow and friendly severed head who asks if you could perhaps kill his body, which is running around murderising people. If you do, then he (thankfully with his now-pacified body attached) can be a summoned ally against the Final Boss.
- Gavlan is the one merchant who will buy your stuff, and his enthusiastic, if grammatically dubious, proclamations of "Gavlan wheel, Gavlan deal!" certainly didn't hurt.
- Sweet Shalquoir, the cat who serves as Lady Exposition, gained plenty of fans due to her friendly, if impish, personality.
- Jester Thomas managed this despite being essentially a blank canvas. He has no backstory and no voice lines. He's an optional summon for one boss fight, which he attends in a full jester outfit complete with cap. He also absolutely trivialises said boss fight by destroying her in an endless barrage of pyromancies. He also invades you in the DLC.
- Sir Raime, the Fume Knight: a terrifying Black Knight with one of the biggest freaking swords in a series where Cloud Strife would feel intimidated. His cool backstory, unique aesthetic and weapon, and battle music that goes as hard as his boss fight meant that he became extremely popular.
- Sir Alonne, one of the few knights in the series who ends up neither corrupted nor cursed, became a fan favourite simply by being a giant slab of pure honour decked out in a samurai outfit.
The third game wraps up the series with some more super-popular NPC's.
- All of the Lords of Cinder are popular, but the crown probably goes to the Abyss Watchers: a Badass Army with a cool and distinctive uniform, descended indirectly from Artorias, with a unique boss fight dynamic - because some of them have been corrupted by the Abyss, the Watchers are a Flunky Boss where the flunkies attempt to kill each other, at least in the first stage. On top of that, their boss soul weapon, the Farron Greatswordnote has a unique and amazingly fun fighting style, where using the offhand parrying dagger causes you to do spins and flips, sword extended all the while, wreaking havoc on tightly packed enemies.
- The Dancer of the Boreal Valley combines a neat aesthetic, a difficult but rewarding boss fight, and a very graceful combat style...with a somewhat disturbingly well-modelled ass.
- The enemies around the Fire Demon's arena in the Smouldering Lake have their own fanbases, because, if provoked, the mimic and skeletons can finish the boss off for you.
- The Nameless King, Gwyn's firstborn, a Chekhov M.I.A. in play since the first game. Even getting to his boss fight arena starts with a Guide Dang It!. When you get there, he looks awesome, rides a dragon, and will kick your ass six ways from Sunday.
- Siegward of Catarina, this games version of Siegmeyer, is possibly this games answer to Solaire in popularity. Not only that, but he gets one of the series very few happy endings.