(Thrym appears as a character in the Book of Legends. The books Ilva Olafson was reading to Eric the night she was murdered.)
Giant. Thrym ("crash") was the ruler of the giants in Jötunheim (Jotunheim). He had stolen Mjollnir, the magical hammer of Thor. Loki found out from the giants, that Thrym will return the hammer to Thor, if he was allowed to marry Freya. It was Thor who dressed himself in bridal gown that went to Jötunheim, instead of Freya.
During the feast, Thrym and the other giants was stunned when they saw Thrym's bride (Thor) ate an ox, eight salmons, and three large tankards of mead. Loki made a silly excuse, telling Thrym that Freyja had not eaten in eight days, because she was excited to be wedded to the king of giants. When Thrym peeped under his bride's veil, the giant was taken back by the fire in Freyja's (Thor's) eyes. Again, Thrym demanded explanation from Loki; Loki answered that Freyja was just excited about the wedding.
When Thrym had the hammer brought in and placed it on his bride's laps, Thor threw off his disguise and attacked Thrym. Thor killed Thrym and all the giants within the hall.