Loki and Baldur/Hoor - In norse mythology, Baldr-was the most handsome youth. He had a visually-handicapped brother named Hoor.
He was having nightmares about his death so,his mommy Frigg asked everyone and everything to swear that they wont kill her son. She didnt ask mistletoe since it seemed too young to ask for an oath.
Loki - the trickster made a weapon using mistletoe and guided Baldr's blind brother Hoor to shoot at his own brother during the gods playful test of Baldur's invulnerability. Unwittingly Hoor killed his brother because of the trickster. Balder's wife fell down dead of grief at the pyre, so her body was placed beside her husband's.
Later in revenge Odin and Giangatess gave birth to "Vali?" who grew to adulthood in one day and slayed Hoor.
Rama and Vali/Sugrivan - Sugriva and his brother Vali were half-monkey half-men. Sugriva and Vali became arch enemies after a minor misunderstanding. Vali by penance acquired boon from Brahma that in any fight, Vali would acquire half of his opponent's energy and skills. Sugriva tricked Vali by challenging him for a duel and he fell right into trap.
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Rama - slayed him behind his back , literally. Rama hid behind a tree and made Sugriva wear a garland(Sugriva and Vali both looked alike - why didnt he try blue trunks and red trunks like the vegas boxers?-I dunno) and killed Vali behind his back.
After slaying his brother Surgriva claimed his wife Ruma who was early kidnapped by Vali and in addition to Vali's wife Tara.
Looks like Sugriva was a true christian. "Go in unto thy brother's wife, and perform the duty of a husband's brother unto her, and raise up seed to thy brother" . The brother gets the wife after his brother's death, doesnt matter if it suicide,homicide or fratricide.
First he followed first brother of the world Cain and killed slayed his brother Vali(Abel) ;-)
Not just the name Vali one another striking similarity in this story is, in same Ramayana, like Frigg , Ravana - the antagonist by penance acquired a boon by giving entire list of things, people by which he cant be killed and missed one entity "human" in that list. And Vishnu took human avatar "Rama" and killed him.
Moral of the story: Always review the list, doesnt matter whether it is grocery list or hitlist to avoid all sort of repercussions later.
Check more comparison mythology stories here