is one piece episode 743 filler?

In response to Law's revelation that he is the boy Donquixote Rosinante cared for, Sengoku states that he had already guessed, but asks Law why Rosinante worked so much to help him. Law tells Sengoku how Rosinante took him to hospitals before getting him the Ope Ope no Mi, and he had spent the thirteen years after Rosinante's death working to kill Donquixote Doflamingo.

However, Law wonders if that was how he should have lived as a D., and Sengoku is shocked that Law carries the initial in his name.