Saint Roswald (Rosward Sei) is one of the World Nobles, whom is allowed to reside in the Holy city of Mariejois.
Roswald is noted to be the most responsible of his family seen, as seen when he scolded his children for their behaviour.
Though he scolds his children he cares for them, has "never hit his son", despite his behaviour and showed deep anger at Luffy for hitting him. Like his daughter Shalulia, he has deep pride for his ancestry. Of his family, he is the only seen who didn't abuse anyone citizen or slave, though he shoots at the Straw Hat Pirates and supported the treatment that his children gave others.
He is first seen with his daughter, Saint Shalulia, looking down on his runaway-blown up slave, Dias, who was the Captain of the Acumate Pirates. After his dog urinates on the man, his daughter shoots him with a gun, displaying no remorse afterwards. A demon-like creature is seen behind him. Later in the story, it is revealed that the demon-like creature is in fact, Pirate Captain Jean Bart.
He is then seen at the Human Auctioning House, with his son Saint Charloss and daughter Saint Shalulia. He becomes displeased with his son, Charloss for bidding on Camie.
When his son was attacked by Luffy, he used his cane (which is a concealed rifle) and started shooting randomly around Luffy, then shouted out for someone to call for an Admiral. Sanji kicks the cane out of hand, followed by Usopp knocking him unconscious, after accidentally falling down from the rooftop and smashing his face into the floor".
He is noted for having a "Pirate Captain collection".
According to his daughter, Shalulia, he has never beaten his own son Charloss, something that the Straw Hats did in their first day on the island. His wife(s) have yet to be seen.
When Hancock speaks of her past, she identifies a man who was "the very vision of terror itself". The man's silhouette shows a hair-style that matches Roswald's family, however the only person in his family that matches the silhouette exactly is Roswald himself.
