If a legendary permanent or an artifact entering or leaving the battlefield causes a triggered ability of a permanent you control to trigger, that ability triggers an additional time.
Also, once again, in 1v1 gameplay, you yourself will be one of the 2 players, meaning your equipment, controlled and owned by you, will fall off the creature because it can't be targeted or equipped by your stuff as soon as it has protection from you, making it quite the useless sword
And yes it has a lot on its text box which makes it more impactful than similar cards like Wilderness Reclamation and Unwinding Clock
Enchantment - Aura Increasing Vengeance Copy target instant or sorcery spell you control
Once the last lore counter goes on The Great Work you can cast all your instant and sorcery spells in your graveyard for the turn, effectively giving you a ton of cards to refill your hand
Excess damage caused by a spell or ability is similar to how combat damage from a creature with trample is handled