In my opinion, the Norse God of Light - Balder has a tragic story. Balder has a dream that he will die, and his mother, Frigg, asks everything in the world to promise not to hurt him. She doesn't think mistletoe will pose a threat, and doesn't get a promise from it. Balder's friends and family throw rocks and other things at him as a game, since nothing can kill him, but Loki saw that Frigg missed the mistletoe. Loki tricks Hodur (Balder's blind brother) to shoot an arrow at him. Hodur thinks it is safe since nothing else has hurt him, and Loki gives Hodur an arrow made of mistletoe. It kills Balder. Frigg goes to the Underworld to ask for her son to return to the land of the living, but to no avail. In order for Balder to return, everything in the world must weep for him, but an old hag in a cave refuses to. (believed to be Loki in disguise) Hearing that Balder is unable to return, Inanna, his wife throws herself on Balder's funeral pyre. Some interpretations of the myth say that Balder represents light (as most savior gods do), Hodur represents darkness, Inanna represents vegetation, and the weeping represents the dew that comes from the "light" or dawn. Mistletoe represents death, as it should, but if you consider that the Norse believed their Axis Mundi was the World Tree, it's not just a symbol or metaphor...
Also, the Greek and Egyptian myths of Orpheus and Eurydice and Izanami and Izanaki are tragic - both husbands travel to the Underworld to ask for their wives back, and in both stories, the husbands turn back to look at their wives before they can get out, cursing their wives to eternity in the Underworld. Egyptian myth has Isis searching for her husband Osiris who was killed by his brother, Set.
