The plot gods have for the desire of entertainment transported Inuyasha and Sesshomaru to the world of The Seven Deadly Sins, both have their swords, and are explained to them by the gods the world, they both get involved with the story. This is both of them at the end of the story.
Scenario 1: This is at the beginning of the story of the seven deadly sins.
Scenario 2: This is at the middle of the story of the the seven deadly sins
Scenario 3: This is at the point that is in between the beginning and the middle of the story.