"Realm King" Odin is the 1st Mate of Yggdrasil's crew. He weilds the Shima Shima no Mi (the Island Island Fruit) that allows him to grow islands out of the sea, the air (kind of like Skypiea), or in the middle of other landmasses (with a ring of water surrounding it). He can control everything on that island, including weather, life, flora, features, raw materials, events, even objects that are technically man-made, such as statues or boats.
Odin is an older man, over 80, with one good eye because the left one is in an eyepatch. Odin has gray hair and usually wears a pirate-captain-like hat. Odin has a lot of battle scars, most notably a long scar that goes vertically over his missing eye, most likey the reason he lost it, and not to mention the peg leg he has. Odin speaks with a loud voice, and has sort of a pirate-ey accent (aargh...).
His theme of dress is meant to convey the idea of a pirate captain; he sports a long, thick, dark black coat as well as a grey shirt underneath. He carries many weapons on his body, some hidden.
His norse god theme is Odin, which reflects in his name, is identified by having some kind of relationship to Loki, Freyja, Thor, Yggdrasil (the eternal tree in norse myths), and his own islands (named after the nine realms of norse myths).
His personality is strict, murderous at times, and much like a stereotypical pirate.
Odin is the newest member, taking PX-TANK's position of first mate upon joining. Odin has yet to build any relationships, though. He does have some relationships though, PX-TANK hates him for stealing it's position, Mr. 22 doesn't care in the least, Mr. 33 likes getting a new crewmate, Yggdrasil thought he would make a good crewmate and respects him, Mr. 77 saw that he has power and admires him, Mr. 88 didn't notice Odin's power at all, and Redhorn says he looks up to Loki so he says he okays the new 1st Mate.
Odin has no connection with his children at all! The only one he is proud of at all is Loki because he is a pirate king, but Freyja and Thor he thinks failed with their lives.
He mastered the Devil Fruit Shima Shima no Mi to the point of perfection where he can create islands and control any and all events there.
All that is known is that at some point Loki, Thor, and Freyja were born, and that he recently joined Yggdrasil.