Jaguar D. Saul

Vice-Admiral Jaguar D. Saul (ハグワール・D・サウロ中将 Haguwāru D Sauro Chūjō) is a former Marine introduced in Nico Robin's flashback during the Enies Lobby arc. Saul is a giant, but unlike previously introduced giants in the One Piece manga, Saul did not originate from the viking-inspired warrior's paradise, Elbaf. Saul is also characterized as having a unique, but awkward laugh ("Dereshi") that he finds somewhat embarrassing.

Saul is the fifth character in the series to possess a "D" as his middle initial, and was the first to explain that the "D" is in fact a family or clan-name. Although there is no solid evidence in support, this leads many fans to speculate that Saul is the grandfather of Monkey D. Luffy; this claim is further inflamed by Aokiji's admission of "dealing with" Luffy's grandfather. In recent chapters belief that Luffy is part giant has increased with fans because of his Gear 3 attacks in which he makes a part of his body a size comparable to that of a giant. However, Luffy can only use his Gear 3 attacks because he ate a devil fruit. The theory that Saul is Luffy's grandfather is mostly removed due to the fact the it has been reveiled that Vice Admiral Garp is Luffy's granfather; however, people have two sets of grandparents.

While on duty, Saul's vessel encountered a wanted ship run by the Archaeologists of Ohara, who left West Blue to locate and decipher the mysterious Poneglyphs that bear an ancient, forgotten history of the One Piece world. Despite ordering his men to take the archaeologists alive, Saul's crew slaughtered all but one; Nico Olvia, the mother of future Straw Hat crewmember Nico Robin. After her capture, Saul was informed by Sengoku that he would be one of the five chosen Vice Admirals to lead a Buster Call against the Ohara for its crimes of deciphering the Poneglyphs. Rejecting the study of history as a justification for the order, Saul, like Smoker, would begin to doubt the Naval doctrine of Absolute Justice".

After interrogating Olvia, Saul grew disgusted with the military's brutal intentions and defected against the World Government by releasing her. Shortly thereafter, he was shipwrecked in a storm, then sent adrift in the ocean until fatefully landing on Ohara itself. There, he met and befriended Nico Robin and was reunited with Nico Olvia. After promising Olvia to ensure Robin's safety, Saul was frozen by Vice Admiral Kuzan (Aokiji). As he was being frozen, Saul smiled and laughed, cryptically echoing the way Gold Roger was executed two years prior.