'One Piece' episodes 768, 769 spoilers: Next episode to reveal significant details on how to become a pirate king

Raizo may not have measured up to the Straw Hat pirates' impression of what a ninja should look like, but coming to his hiding place in a secret room inside the Whale Tree's tail brings about a revelation that none of them would have expected to see at such a place.

"One Piece" episode 768 finally brought Luffy and his crew face-to-face with the infamous Raizo, the ninja whose purported absence from the island almost cost its complete destruction at the hands of the Beast Pirates. It turned out that he has been there all along, and has been kept hidden and alive owing to the island's secret alliance with the Wano Kingdom. The upcoming episode 769 may feature the Straw Hat Pirate coming to terms with the sad fact that Raizo does not match any of the impressions they have of what a ninja should look like.

Titled "A Red Stone! A Guide to the One Piece!" also brings the Straw Hats to one of the four Road Poneglyphs that are rumored to contain very important details on how to get to the island of Raftel. This red poneglyph may bring Luffy several steps closer to realizing his dream of becoming a pirate king.

The episode preview also shows Luffy and his crew seemingly goading the ninja Raizo to show them his skills and thus erase whatever doubt they may have had about his credibility. Will they finally be able to see a true-blue ninja in action, or will Raizo end up being annoyed and throw them out of his lair instead?

The episode is based on the second half of the "One Piece" manga chapter 817 and may continue to the earlier parts of chapter 818 as the Straw Hat Pirates find out more details about the steps to becoming a pirate king.

Raizo the Ninja features veteran voice actor Masashi Ebara who also provided the voices of Mighty Guy from "Naruto" and Cowboy Andy from "Cowboy Bebop."

"One Piece" episode 769 airs on Sunday, Dec. 18, at 9:30 a.m. Japan time on Fuji TV.