The opening cinematic reveals that Aldrich has become an expansive sludge of maggot-ridden rotten flesh, humanity dregs, and his own bones as well as those of the victims he has consumed.
By the time the player reaches him, he will be inert and spread across the floor, using the weapons and malformed body of Gwyndolin to interact with his environment and perform attacks.
Formerly a holy cleric, he began to have visions of an age of the "deep sea," where the dregs of the human soul fall to their lowest depths and become the shackles which bind the world. Through these visions, Aldrich was able to reach a level of the Dark generally inaccessible to humanity, which subsequently came to be known as the "Deep." Aldrich eventually developed a habit of consuming humans, an act in which he delighted.
Building on these visions and powers, Aldrich founded the Church of the Deep and actively pursued the corruption of human souls. The clerics of the Church sheltered him and provided him with a steady stream of sacrifices, an operation overseen by Archdeacon McDonnell and Archdeacon Royce.
During this time, he continued to indulge in the misery of those he consumed, and even created sacred rings that bestowed that same feeling to wearers. But while the powers in the Deep are beyond pure humanity, so too is its potential to do grave harm, breeding abhorrent life beyond abyssal corruption. Most of those who worshiped the Deep became intoxicated or corrupted, all except for Aldrich, who, despite his taste for flesh, retained sanity somehow. He was not immune however, and his devouring of both flesh and souls bloated him with dregs until he collapsed in on his own polluted form, becoming a mass of abyssal sludge, animated by darkness. Despite this, he retained sanity and sentience, and was still given his sacrifices.
Why he linked the fire is unknown, but some believe he was forced to by the time's rulers as his strength had made him the perfect candidate. All that is known is that he was not chosen for his worthiness, but for power he held.
After Aldrich was revived as one of the Lords of Cinder, he experienced visions of the world's inevitable envelopment in darkness, and neglected to take his throne. He began dreaming of the Old Gods, who supported the linking of the fire, and sought to devour them. Sulyvahn traveled with him to Anor Londo and managed to capture Gwyndolin, God of the Darkmoon. His younger sister, Captain Yorshka, was imprisoned above her own church by Sulyvahn, while Aldrich began consuming the God of the Darkmoon.
As Aldrich took to devouring Gwyndolin's body, he appears to have entered hibernation, falling into a deep slumber. In his sleep, Aldrich was also able to absorb Gwyndolin's memories, as he dreamed about a young, pale girl in hiding. When the Ashen One arrives to slay the devourer, Aldrich awakens to defend himself, utilizing Gwyndolin's powers/body and a miracle developed from his dreams.
The encounter begins with Aldrich standing on the far end of the room, imbuing his staff with magic and wielding it menacingly while he prepares for battle. He specializes in ranged combat, doing so by casting diverse dangerous magical spells. Conversely, his close combat abilities become heavily compromised due to his sluggish mobility and tendency to miss hits with his weapon. His substandard melee abilities should not be underestimated, however, because what he lacks in accuracy, he more than makes it up in damage-dealing potential.
When he rears up and aims his bow, he will launch an expanding wave of highly damaging arrows in front of him, allowing you to circle behind him and get hits in.
Throughout the course of the battle, Aldrich will be constantly summoning small homing projectiles. Each one of these, on its own, only deals a small amount of damage and the player may even opt to sustain a few of them in exchange of inflicting some damage to the boss. However, if they are caught by the full attack, they will sustain heavy damage, which may even kill them in a single barrage.
Aldrich is most vulnerable on his tail, which provides an area where the player may attack without risking themselves too much from being in the staff's range.
Upon receiving some damage, Aldrich will raise his staff and create a big vortex on the ground in front of him, plunging inside to escape from punishment. This vortex is heavily damaging and the player would be wise in not attacking the boss too many times in a row, preparing instead to move away when it is cast. Aldrich will emerge a moment later on the other side of the hall, as far away from the player as possible, trying to buy some time to cast more spells.
Once Aldrich has lost about 40% of his health, he will buff his scythe with fire. At this point, every time he emerges from the ground, he will deal damage to nearby players while a much greater amount of homing projectiles spawn with him as he rises.
He will also use a replica of the Lifehunt Scythe, starting a large windup before spinning twice in a full circle, and stealing health with each target that it connects to. This attack is telegraphed, and one can see the miracle generating on his staff, but it can often be confused for another standard swing.
His most devastating attack is, without a doubt, is taking out Gwyndolin's bow and shooting toward the sky, making an extensive barrage of arrows rain over the player and follow them for a considerable amount of time. He telegraphs this attack by suddenly stopping and erecting his upper body, while a white flash of light emanates from him. Being caught under the rain of arrows, practically means instant death. As soon as this attack is detected, the player is advised to completely disengage from battle and start running throughout the room with no specific direction.
At the beginning of the fight, charge at Aldrich to avoid his hard-hitting soul spear. Get behind him and focus your attacks on his tail. This leaves him with nothing to do but swing his two slow, devastating melee attacks or teleport across the room (usually, adjacent to where he teleported from).
At about 55%-60% health, he will teleport and come back up, buffed with fire. His arrows also go from going forward to following a specific player. If the arrows following the player catch up to them, then that player will most likely go down quick. Blue Bug and Red Bug Pellets are recommended for this fight.
Casting the sorcery Twisted Wall of Light can negate Aldrich's ranged attacks, including his arrow barrage in the second phase, allowing one to wait out the attack by casting repeatedly.
Soul of Aldrich
Cinders of a Lord
- Aldrich is susceptible to Vow of Silence, which will block most of his attacks.
- Aldrich is considered an abyssal enemy, and takes extra damage from the Wolf Knight's Greatsword and Farron Greatsword.
- Hitting Aldrich in different parts of the body affects how much damage is dealt.
- Attacks on the sludge/tail deals normal damage.
- Attacks on the body below the waist deals 50% more damage.
- Attacks on the body above the waist deals double damage.
- Aldrich's throne in Firelink Shrine refers to him as "Saint Aldrich of the Deep".
- Aldrich's appearance resembles an amalgamation of Gwyndolin and Nito from Dark Souls. A connection to Priscilla is also implied as Aldrich can summon a Lifehunt Scythe.
- During the fight, as well as when the boss is passive, shrieks and moans of pain can be heard coming from Gwyndolin. As Aldrich was half-way through consuming Gwyndolin and had used the God's body to defend himself, this disturbingly implies that Gwyndolin was still alive (albeit barely) and in a semi-conscious state of being continuously devoured by Aldrich, even during the fight.
- While the attacks of Gwyndolin were light blue energy that dealt magic damage in the first game, Aldrich uses variations of the same attacks with purple energy that dealt dark damage.
- Innumerable bones and large amounts of sludge can be seen on the floor of the arena, similar in appearance to Aldrich himself, and possibly being actually part of his body. If this is the case, then, Aldrich insists on attacks by exerting his will over the body of Gwyndolin, instead of simply devouring the player.
- The sludge and bones remain after Aldrich dies, though they are inert, making him and Archdeacon Royce the only two bosses to leave behind physical remains.
- His melee attacks, during his first phase, closely resemble those of Nito.
- Aldrich's staff uses a Dark Miracle version of Nito's Gravelord Sword.
- His name, besides being an actual name, may also be a play on the word "eldritch", meaning esoteric or mysterious.
- Aldrich's staff, presumably inherited from Gwyndolin, bears a semblance to the Golden Ritual Spear.
- In the soul of Aldrich, there is a distinct lighter portion inside the soul that is not present in other deep soul; the meaning of this is unknown.
- The comic Dark Souls: The Breath of Andolus features a scryer named Aldrich as the deuteragonist, potentially as a reference to him, despite them not being the same character.
- The music played during his fight is a more sinister and macabre arrangement of Gwyndolin's theme from the first game, as he uses the body of the god to defend himself.
- Dialogue with Anri of Astora.
- Human Dregs description.
- Deep Gem description.
- Aldrich's Ruby/Sapphire description.
- Soul of Aldrich description.
- Great Deep Soul description.
- Gnaw description.
- Deep Protection description.
- Dorhys' Gnawing description.
- Dialogue with Hawkwood.
- Executioner Set description.
- Lifehunt Scythe description.
- Aldrich's in-game sounds during the fight and when he is passive.