is one piece episode 381 filler?

Brook told Monkey D. Luffy that he was truly glad to be alive despite the trials he had experienced since reviving over 50 years before.

Brook asked if Luffy's original invitation to join the Straw Hat Pirates was still open, and Luffy accepted him as part of the crew. All the Straw Hat Pirates were shocked by this, except for Roronoa Zoro, who was sleeping, and Nico Robin, who knew Luffy would accept him no matter what, but they nevertheless welcomed him to the crew.