Eris Morn

Eris Morn is a former Hunter and sole survivor of the ill-fated attempt on Crota's life. She lost her Ghost, her Light and her friends to the Hive, and is eager to make them suffer as she once did. She played a major role in the death of Crota, as well as Oryx, Omnigul, and Hashladun.

Attack on the Hellmouth
Eris participated in the initial attempt to retake the Moon from the Hive, where hundreds of her fellow Guardians were slain by the Hive, who were led by Crota. After consulting with Eriana-3, they decided to seek out Toland, the Shattered for their plan to assassinate Crota. They also recruited the Hunters Sai Mota and Omar Agah, and the Titan Vell Tarlowe, bringing the total number of members of the fireteam up to six. In the end, however, she was the sole survivor of the fireteam, after they entered the Hellmouth, seeking to kill Crota, but were slaughtered by Crota and his armies.

In the process, Crota somehow severed her connection to the Traveler, and took away her light. This gave her a dark, desolate appearance, of prominence being the green, three-eyed visage of the Hive. For years, Eris was forced to hide in the vast tunnels that the Hive dug in the Moon's surface, studying them and learning many, many secrets previously unknown to Earth. Eventually, she managed to construct a ship from scavenged material, and escaped the Moon.

The Dark Below
She returned to Earth at the onset of Crota's return. She aided the Vanguard and the Guardian in repelling Crota's armies, his disciples, and eventually killing the Hive Prince himself.

The Taken King
After the fall of his son, Oryx traveled to the Solar System in the Dreadnaught, to seek vengeance upon the Guardians. Eris was permitted to move into the Hall of Guardians, and given a greater role in the war against the Taken King, sharing her intimate knowledge of the Hive. Cayde modified her jumpship with stealth drives in an attempt to board the Dreadnaught, but it was ultimately destroyed. Eventually, the Guardian managed to force Oryx to retreat, though was later pursued to the depths of his ship, and vanquished for good. After his initial defeat, Eris approached Oryx's sword, Willbreaker, which was buried in the god's altar, and retrieved its core.

Shadowkeep
After the Red Legion attacked the Last City, Eris Morn fled the Tower and went into hiding. During her self-imposed exile, the Cabal Emperor Calus considered recruiting Eris Morn as his Shadow of the Hive. She remained in hiding for 2 years until she eventually returned to the Moon, where she accidentally awakened a powerful and ancient evil that had been sleeping beneath the surface for centuries that had the power to resurrect enemies of the Light. She would eventually call upon the Young Wolf, alongside other Guardians for assistance in defeating this evil, as well as the Hive who served it.

General
Eris is a vendor in the Tower in Destiny. She offers bounties and gear related to The Dark Below and The Taken King. She returned in Destiny 2: Shadowkeep as a vendor on the Moon.

Crota's Bane
Eris Morn features a faction-like reputation system to unlock various The Dark Below and The Taken King items. The following is a table of reputation requirements and items that can be unlocked.

Faction Rewards

 * Dark Harvest (Emblem)
 * Sigil of Night (Emblem)
 * Blade of Crota (Emblem)
 * Predawne (Shader)
 * Middaye (Shader)
 * Sunsetting (Shader)
 * Mark of the Spawn
 * Mark of the Hidden
 * Hood of the Spawn
 * Cloak of the Hidden
 * "Emerald Light"
 * "Song of Dusk"

Supplies

 * Special Ammo Synthesis
 * Heavy Ammo Synthesis
 * Reciprocal Rune
 * Stolen Rune
 * Moldering Shard

Quotes

 * "And with the lone strength of the Titan Vell Tarlowe, we felt invincible."
 * "Mota was so close -- clawing her way out with bones torn from Acolytes. Her fall -- Omnigul. You honor her."
 * "The shadows dance quickly among the dust. Make them your ally."
 * "That Prison holds nothing that does not want to be there. Knowing that, ask yourself, 'Why do the Taken stay?'"