When your in a fight, playing as Lightning. Go to tehcniques and Summon Odin should be there, but you have to make sure you have enough TP. You need to have at least 3 TP to summon.
You can find the Deathbringer after you face Lunar Odin.
Gods are not demons: they can not be "summoned".
Serah Farron, Noel Kreiss and a wide variety of tamable monsters. Lightning and Odin make a brief playable appearance at the beginning.
Six, one for each character. Lightning - Odin Snow - Shiva Sisters Sazh - Brynhildr Hope - Alexander Fang - Bahamut Vanille - Hecatoncheir
The Summon Materia are Choco/Mog, Shiva, Ifrit, Ramuh, Titan, Odin, Bahamut, Leviathan, Kjata, Alexander, Neo Bahamut, Phoenix, Hades, Bahamut ZERO, Typhon, and Knights of the Round.
Yes get GF tonberry at Centra Ruins (where you got/can get Odin - you must get Odin first) There, kill around 20 or so Tonberrys and King Tonberry will appear. Kill him and you will get the GF. Tonberry can learn the Call Shop ability, which lets you shop at places no longer available. The Esthar Book Shop will have Combat King 004.
In Norse mythology Odin was a god, but he was devoured by Fenris (Fenrir the wolf) during the battle of Ragnarok, and so technically is no longer one. Odin was the "Allfather" of Norse mythology, and the first of the Aesir (gods) to be born. Ironically, as the eldest, strongest and wisest, he was also the first to die when the final battle came.
Odin does not hate Thor, Thor is the son of Odin.
See 'What powers does Odin have?'
Odin was married to Frigg.
Odin isn't real
Odin is often associated with the Old Norse language, which was spoken by the Norse people in Scandinavia during the Viking Age. It is a Germanic language and was written using the runic alphabet. However, there is no definitive evidence to suggest that Odin himself had a specific language.