The spiky crystal statues that are found periodically in The Depths, the Crystal Cave and the Duke's Archives are actually the bodies of other players who had been killed by being cursed.

Three unused rings can be found within the game's data. These rings are:
• Ring of Displacement: This ring takes damage in place of its wearer, but has a fixed chance of breaking
• Ring of Blind Ghosts: It prevents its wearer's discovery by cursed ghosts.
• Ring of Condemnation: granted to those who enter a Covenant with Velka, the Goddess of Sin.

Despite the two games being in separate universes/worlds, Patches the Hyena from Demon's Souls appears in Dark Souls under the same name. His role in Dark Souls is also the same as in Demon's Souls.

Unused dialogue from Ingward suggests that the player was supposed to fight "a Darkwraith, a servant of the Four Kings" before obtaining the Key to the Seal.

This dialogue may refer to the Undead King Jar-Eel, a cut boss from the game, as one of King Jar-Eel's weapons is a Dark Hand, which is used frequently amongst Darkwraiths.

Hidetaka Miyazaki, the director of Dark Souls, said that the Pendant gift had no use in the main story, and that he had only added the item to play a joke on the players. However, whenever Miyazaki plays the game, he would either pick the Pendant or nothing as a starting gift.

Unused text from the game's data reveals that Shiva of the East's main goal is to obtain the Chaos Blade. If the player manages to get one, Shiva will even go as far as attacking the player to obtain it.

There is an unused Miracle called "Escape Death" in the game's files that acts as a Rare Ring of Sacrifice, letting the player die, but also keep all of their souls and humanity. It is likely that this was removed due to developers noting that it would remove the penalty of death, making the game unbalanced.

Oscar, Knight of Astora (the knight who gives the player the Estus Flask in the Undead Asylum) was likely supposed to take a more prominent role. Unused dialogue in the game's files suggests that he was supposed to help the player in Darkroot Garden, as well as engaging in a confrontation with the player at some point in the story.

It is commonly speculated that Gwyndolin was a son of Lord Gwyn raised as a woman due to his affinity to the moon. Unsurprisingly this leads to him having feminine traits such as long hair, fair skin, and feminine clothing. But surprisingly he also has breasts. This is because the character model used for Gwyndolin is a female character model, despite the fact the character is actually male. This trait is also present in the Dark Souls Art Book.

In the Prepare to Die Edition, the player has an opportunity to save a young Sif from the Abyss. After doing so and summoning Sif for a boss fight deep in the Abyss, if the player has not yet defeated Sif in the present, the opening cutscene will change.

Sif appears to recognize the player, and is reluctant to do battle with them, but finds it necessary, likely due to Sif swearing to protect the grave or the Covenant of Artorias. This cutscene makes the hobbling animation when Sif is at low health even more heart-wrenching for some players.

The Bounding Demons in Lost Izalith are actually made from the same mesh as the lower half of the Undead Dragon minibosses. Neither of the two Undead Dragons ever stand, and the one in the Painted World Ariamis crawls forward and disconnects from its lifeless lower half. There is a glitch where attacking the lower half when you can reach it with a plunging attack will prompt the body to shoot up onto its legs like a Bounding Demon, thus eliminating the need to unlock several doors and pass through a fog gate.

New Londo, in the game's lore, is a city that was submerged in a flood of water in order to prevent the spread of the Abyss and the Darkwraithes. The city is populated by the vengeful ghosts of those who were martyred in order to prevent the spread of the Abyss. In the New Londo Ruins, the two Banshees that players can encounter are clutching what appear to be their babies to their chests.

The in-game descriptions of the Mask of the Sealer and the Remedy sorcery speak of two other Sealers aside from Ingward who abandoned their duty to watch over the Seal of New Londo. One Sealer, Yulva, is said in the Remedy description to have gone to Blighttown to cure the sick. It can be speculated the corpse where the Crimson Set, Tin Banishment Catalyst and Remedy spell, all of which would be associated with a Sealer, is her.

The second is unnamed, but there is only one other male NPC in the game who wears the complete Sealer set, sans the mask. It is worth noting that the Mask of the Sealer was a "symbol of their resolve", which he would lack had he abandoned his duty. In Anor Londo when confronting Lautrec with the Black Eye Orb, he can be seen assisting Lautrec as a White Phantom. Seeing as Phantoms exist outside of the player's true timeline, it is unclear whether or not the man remains alive in the game's present.

The Ceaseless Discharge, who is revealed to be the only son of the Witch of Izalith by the in-game description of the Orange Charred Ring, can be instantly killed if provoked into attacking the player after they remove the Gold Hemmed set from the altar near him. Provoking him into attacking the player there specifically and then running back to the Fog Gate makes him charge after the player and leap over the chasm below to try and stop them from escaping. The result leaves him desperately grabbing the ledge, from which point the player can attack his arm and send him falling to his death.

Despite the name, the Four Kings fight can produce more or in rare cases less than Four Kings. This is due to the nature that the boss fight itself is one health bar shared between however many kings required to empty it, with a new king spawning every minute there is less than four. Because of this spawning, if a player kills three kings and fails to kill the fourth fast enough, three more kings can eventually spawn with full health on the individual monsters, but no additional health added to the total health bar. The health also seems to increase when Phantoms are summoned to assist the player.

On the flip side, under the right conditions there can be as little as ONE king spawned that still results in victory for the player. Kings cannot INDIVIDUALLY be damaged when performing their Lifedrain grab, but attacking a king in the middle of the animation does damage to the total Kings lifebar. They are still able to be damaged during their death animation as well, and with enough players and the proper buffs, this makes killing less than four of the Kings possible.

Though ill-advised for an inexperienced player, a surprising number of boss fights are optional. Certain fights, such as the Taurus and Capra demons in the Undead Burg, can be bypassed by choosing the Thief class or choosing a Master Key as your Gift when building a character. Some are simply well-hidden, like the Stray Demon, Crossbreed Priscilla (who does not even start out hostile), and Dark Sun Gwyndolin. The Demon Firesage and Centipede Demon can be bypassed by being a high-ranked member of the Chaos Servant Covenant, and finally, perhaps the most difficult to bypass of all, the Ceaseless Discharge can be avoided by having enough vitality, healing, fire protection and speed to run across the molten lava he produces in the Demon Ruins.

Lautrec of Carim is a very obvious nod to Yurt, the Silent Chief from Demon's Souls. Both are heavily armored with their faces covered, both use twin shotels and parrying daggers, both are first found imprisoned and imploring that the player help free them, and both eventually begin to murder other NPCs. The difference is the scope of their killing; while Lautrec is limited to one murder, Yurt can murder nearly all the NPCs in the Nexus.

Even more embarrassing than the fact it can be defeated by Black Iron Tarkus without any aid from the player on an initial playthrough, it is possible to knock the Iron Golem completely off the battlefield when he loses his balance, resulting in an instant death for the boss.

Unlike the majority of characters throughout Dark Souls, Sieglinde of Catarina, the daughter of Siegmeyer, is speculated to be a human. All the human characters met in Dark Souls are either Undead, who are reborn at Bonfires at the cost of their humanity until they are completely Hollow, or are non-human in some other regard. This makes her quest to find her father all the more treacherous, given the fact that the moment she dies, she is dead for good.

Subtle references and similarities to Kentaro Miura's manga "Berserk" can be found hidden in the game. The earliest example that can be discovered is the blacksmith Rickert, the name of a character in Berserk who was also a blacksmith.

Beatrice the Witch, who can be summoned twice as a Phantom for boss fights, bears a striking resemblance to the Berserk character Schierke.

The main character of Berserk, Guts, can also be seen referenced in a few different ways. A much more subtle reference is Black Iron Tarkus, a character summoned as a Phantom and seen later as a corpse in Anor Londo. His black armor and greatsword are said to be absurdly heavy and only able to be donned by him due to his incredible strength. Guts, while his armor is somewhat differently designed, is known for wielding weapons of absurd weight, and was also known for wearing black armor. What's more, the design of the Dark Souls Greatsword resembles the design of one of Guts' earliest swords.

The second reference is contained within the Dark Souls DLC in the form of Artorias, the Abysswalker. Some similarities include the design of Artorias' armor and Guts' Berserker Armor, their swords' abilities to damage demons and ghosts, their symbolism and references to wolves, their mangled left arms and their losses of sanity (though for varying reasons). In addition to that, many of Artorias' poses both for the DLC promotions and for in-game cutscenes greatly resemble official artwork of Guts from Berserk.