Syr Gwyn, Hero of Ashvale
Legendary Creature — Human Knight
Vigilance, menace
Whenever an equipped creature you control attacks, you draw a card and you lose 1 life.
Equipment you control have equip Knight 
.
Squires throughout the realm aspire to her mix of panache and martial prowess.
Lie Setiawan
Throne of Eldraine (ELD)
• #330Rulings
If Syr Gwyn leaves the battlefield after an equip Knight ability has been activated, that ability still resolves even though the Equipment has lost that ability.
(wotc • 2019-10-04)
Syr Gwyn's triggered ability triggers once per attacking creature that's equipped, regardless of how many Equipment those creatures each carry.
(wotc • 2019-10-04)
Whether the target creature is a Knight is checked only as the equip Knight ability is activated and as that ability resolves. If the creature somehow becomes a non-Knight creature later, the Equipment remains attached to it.
(wotc • 2019-10-04)
Equipment you control still have their other equip abilities in addition to equip Knight {0}.
(wotc • 2019-10-04)
Rulings
If Syr Gwyn leaves the battlefield after an equip Knight ability has been activated, that ability still resolves even though the Equipment has lost that ability.
(wotc • 2019-10-04)
Syr Gwyn's triggered ability triggers once per attacking creature that's equipped, regardless of how many Equipment those creatures each carry.
(wotc • 2019-10-04)
Whether the target creature is a Knight is checked only as the equip Knight ability is activated and as that ability resolves. If the creature somehow becomes a non-Knight creature later, the Equipment remains attached to it.
(wotc • 2019-10-04)
Equipment you control still have their other equip abilities in addition to equip Knight {0}.
(wotc • 2019-10-04)