Tally Lang

Tally Lang is the leader of a group of Blood Eagles in Appalachia.

Background
Ostensibly, Tally Lang is a poor, innocent orphan who has visited Fort Atlas to acquire guns from the recently-arrived Brotherhood of Steel, so that she and her friends can properly defend themselves from the dangers of Appalachia. In reality, she is a raider, seeking to get ahold of hi-tech weaponry to make her gang more powerful.

Some time later, Tally and her group of Blood Eagles stormed into Vault 96, trailing some Hellcats and looking to loot the vault. This led to the death of Woods and many mercenaries. Tally's group accidentally becomes locked in. The Vault Dweller encounters Tally through an intercom and she requests for help, offering a vault keycard in exchange. Tally is apathetic towards any Blood Eagles the Vault Dweller killed prior, and does not care about trying to save the rest of the group who may be still stuck inside, saying they're not her problem.

Quests

 * Forging Trust: Tally is one of four civilians inside Fort Atlas, each with their own problems and requests for the Brotherhood of Steel. Knight Shin asks that the player character interview these civilians, though ultimately Shin discards Tally's request. Shin vehemently denies the prospect of giving valuable weaponry to a wasteland civilian, and this can be reinforced with the suspicion that she may be a raider.
 * A Satisfied Conscience: Tally is in possession of a keycard needed to progress through the Vault but the Vault Dweller must save her and her gang members from attacking Mister Gutsies.

Other interactions
Tally constantly denies that she is a raider when asked, although Knight Shin has his own suspicions about her. If the player character had sided with the Crater Raiders in order to access Vault 79, they can affirm to Tally that they are friends with Crater, upon which she will quickly tell the player character to keep quiet about her association with the Raiders.

Appearances
Tally Lang appears only in Fallout 76, introduced in the Steel Dawn update and expanded upon in the Steel Reign update.

Behind the scenes
When Tally tells a Crater-allied player character to stop mentioning the Raiders, she will tell them to "ix-nay on the Ater-Cray!" This is Pig Latin, with "ix-nay" in particular being a phrase that has entered common informal usage in English.