Dack Fayden — ruling 1

The targeted player draws two cards and discards two cards all while Dack's first ability is resolving. Nothing can happen between the two, and no player may choose to take actions.

Dack Fayden — ruling 2

The ability of Dack's emblem will resolve before the spell that caused it to trigger.

Dack Fayden — ruling 3

The effect of Dack's second ability and the effect of the emblem's ability last indefinitely. You won't lose control of the permanents if Dack leaves the battlefield.

Dack Fayden — ruling 4

If you gain control of a permanent, and you leave the game, the control-changing effect will end. Unless there's another control-changing effect affecting that permanent, it will return to its owner's control.

Dack Fayden — ruling 5

If you gain control of a permanent another player owns, and that player leaves the game, the permanent will also leave the game.

Dack Fayden : règles, fonctionnement et interactions (MTG)

Dack Fayden is one of those cards players keep asking about. Here is, in plain words, what its official text says, the rulings published by Wizards of the Coast, and the combos players actually run.

Official card text

+1: Target player draws two cards, then discards two cards. −2: Gain control of target artifact. −6: You get an emblem with "Whenever you cast a spell that targets one or more permanents, gain control of those permanents."

How it works : Dack Fayden

Original English text — Wizards of the Coast / Scryfall

#1June 8, 2016· Wizards of the Coast
The targeted player draws two cards and discards two cards all while Dack's first ability is resolving. Nothing can happen between the two, and no player may choose to take actions.
No other card is named in this ruling.
#2June 8, 2016· Wizards of the Coast
The ability of Dack's emblem will resolve before the spell that caused it to trigger.
No other card is named in this ruling.
#3June 8, 2016· Wizards of the Coast
The effect of Dack's second ability and the effect of the emblem's ability last indefinitely. You won't lose control of the permanents if Dack leaves the battlefield.
No other card is named in this ruling.
#4June 8, 2016· Wizards of the Coast
If you gain control of a permanent, and you leave the game, the control-changing effect will end. Unless there's another control-changing effect affecting that permanent, it will return to its owner's control.
No other card is named in this ruling.
#5June 8, 2016· Wizards of the Coast
If you gain control of a permanent another player owns, and that player leaves the game, the permanent will also leave the game.
No other card is named in this ruling.

Interactions with other cards

These cards' text mentions Dack Fayden.

Dack Fayden, Helping Hand

When Dack Fayden enters, reveal cards from the top of your library until you reveal X creature cards, where X is the number of opponents you have. Put those creature cards onto the battlefield, then shuffle. They're goaded for the rest of the game. For each of those permanents, choose a different opponent. Each opponent gains control of the permanent for which they were chosen.