Great Grey Wolf Sif

Great Grey Wolf Sif is a boss in Dark Souls.

Location
Sif can be found in Darkroot Garden behind large, glowing doors, guarding the grave of Artorias the Abysswalker, one of Gwyn's four knights.

Artorias of the Abyss
Sif makes an appearance in the Artorias of The Abyss DLC. The player finds the wolf located behind an Illusory Wall after being led about by Alvina in the Chasm of the Abyss. Sif is found protected by a magical barrier, which was created by Artorias using his Greatshield in order to shield the wolf from the corruption of the Abyss. Upon reaching Sif after defeating the Humanity Phantoms, Sif will vanish and leave behind Artorias' shield. Sif can be summoned during the battle against Manus, Father of the Abyss, after being rescued by the player.

If the Chosen Undead saves Sif in the Chasm of the Abyss before killing Sif in Darkroot Garden, a different cutscene will play before the fight; however, this can only be done if the player places the Lordvessel in the altar through Firelink Shrine, as Artorias' ring is needed to access Kaathe. In the cutscene, Sif will recognize the player as they approach and let out a whimper. The protagonist reaches out to pet the wolf, but Sif pulls away and howls mournfully before sadly picking up Artorias' greatsword. The fight will continue as normal after this point.

Strategies

 * For melee fighters, getting underneath Sif is generally the best strategy, as it makes most attacks miss the player character completely. Care must still be taken to dodge, block or move out of the way of the slam attack, though. Locking on is not always a good idea when doing this, as it can make the camera spin and make it harder to control one's position. Two-handing is more effective, as it will make the fight shorter and reduce the number of slams that need to be dodged.
 * For ranged characters, players can simply target-lock Sif and kite Sif backwards around the edge of the arena. Staying as far as possible away from Sif will cause most, if not all, of Sif's attacks to miss.
 * Using miracles, sorcery, or pyromancy to soften Sif up before moving in with melee attacks can also prove to be effective.
 * Using a summoned phantom as a decoy can make positioning oneself under Sif easier. In a party of two or more players only one should try to get under Sif, otherwise players may bump into each other when trying to dodge Sif's attacks.
 * Sif's attacks can be blocked, but most of them will cause a significant loss of stamina, even with a good shield. Learning Sif's attack patterns and avoiding them completely, either by dodging or simply walking out of the way, is highly recommended.
 * Before the player enters through the fog gate, there is a broken piece of bridge to the left that can be jumped onto. This is most easily accomplished by unequipping all gear beforehand. After reaching the bridge there is another pile of rock resting at the top that can easily be reached through jumping. When at the top, Sif will be visible. Sif will be unable to reach the player, but the player will be able to damage Sif with arrows or other ranged attacks.

Dashing Slice
Like all of Sif's attacks, this can be blocked. If Sif switches the sword to the right side the attack will be followed by a Sword Slam.

Spinning Slice
Sif repositions the sword to a straight position, and spins around twice. Causes massive stamina damage if blocked and can kill players if the slices connect. However, if Sif is at low enough health to where it is limping, Sif will only spin the sword once. Can be dodged by backing or rolling away before the attack is unleashed. Sif will pause afterwards, creating an opportunity for attack.

Sword Slam
Sif slams the sword into the ground. Powerful, but has no tracking and poor hitbox. This attack is only used as a follow-up to Dashing Slice and Finishing Combo.

Evasive Slice
Sif will attempt to slice the player while jumping backwards and away from the player in one motion. Has little to no starting lag. Blocking it won't give the player an opportunity to attack, but will help the player survive.

Single Slice
Sif will do a quick chop from side to side. Good tracking and high hitbox. Possible to roll underneath it with good timing. Also does not do much damage to the stamina bar, thus it can be blocked quite easily.

Double Slice
Two slashes from side to side. Great tracking, thus very difficult to sidestep. However, the slices can be rolled under and blocked fairly comfortably without the stamina bar being fully drained. If Sif is at the point of limping, the wolf will fall on its side and struggle to get up on attempting the second slice, so use this to your advantage to do some damage.

Finishing Combo
Sif will slice twice and then finish with a Sword Slam. The last attack has poor tracking and a small hitbox, so use this as an opportunity to get some hits in.

Trivia

 * Sif is a traditionally female name in Nordic society (specifically, it's the name of a goddess of Earth); however, Sif's actual gender is never stated within the game.
 * Sif means "bride" or "wife" in Old Norse, and it derives from the verb, sifjar, which translates to "affinity or connection by marriage". The name also shares origins with the Anglo-Saxon noun sib, which means "family", and the Gothic verb sibja, which means "to display friendship or love". It is then possible that the name was chosen as a symbolic reference towards Sif's strong relationship with Knight Artorias.
 * Additionally, Saif or Sayf, which means "sword" in Arabic, may be a possible inspiration for the name. Quite befitting, considering Sif wields a sword.
 * In the untranslated Japanese version of the game, its name is Hai'iro no Dairô Shifu (灰色の大狼シフ). The Japanese kanji, Shi and Fu (シフ), are usually combined to represent either the Nordic first name, Sif; or the Germanic last name, Schiff. Interestingly, Hai'iro no Dairô (灰色の大狼) means "Grey Direwolf", rather than "Great Grey Wolf". Due to a lack of grammatical gender in the Japanese language, it is difficult to determine a character's gender unless stated directly.
 * There are translations of the game that use masculine vocabulary when referring to Sif. In the French version, its name is translated as Le Grand Loup Gris, and in the Spanish version as El Gran Lobo Gris. Loup and Lobo are both masculine terms for wolf, while Louve and Loba are both feminine terms for wolf.
 * In the fight against the Chosen Undead, Sif wields the sword of Artorias, former companion who sacrificed himself in order to protect Sif.
 * The sword Sif carries in their mouth appears to be a replica of Artorias' sword. The sword also apparently changes size between the events of Artorias of the Abyss and the main game.