InsaneJournal

For those not keeping score, Loki makse the shocking reveal that Balder is a son of Odin, half-brother to Thor! Loki swears she's telling the truth -- and that Thor has always known -- then goes on to tell how at one of Odin's victory feasts, the Allfather met a woman that caught his eye. Frigga -- who was Odin’s wife in Walt Simonson's run -- eventually gave birth to Balder.

Odin has strange visions about his son in his dreams, and so he traveled far to find the buried remains of an ancient prophetess in order to find answers. She told Odin the prophecy about Balder's death and rebirth. Balder dies at the beginning of Ragnarök but would be the only one reborn afterwards, thus continuing Odin's lineage. However, if Balder were to die before Ragnarök began, he would not come back. This would mean the end of Odin's bloodline. To protect Balder from enemies, Odin kept this secret from everyone except Thor. It's not said how Loki found out, though.

Balder confronts Thor and with a lot of nudging from Loki, Thor officially declares Balder a prince of Asgard!