Balder, Old Norse Baldr, in Norse mythology, the son of the chief god Odin and his wife Frigg. Beautiful and just, he was the favourite of the gods. Most legends about him concern his death. Icelandic stories tell how the gods amused themselves by throwing objects at him, knowing that he was immune from harm. The blind god Höd, deceived by the evil Loki, killed Balder by hurling mistletoe, the only thing that could hurt him. After Balder’s funeral, the giantess Thökk, probably Loki in disguise, refused to weep the tears that would release Balder from death.

Some scholars believe that the passive, suffering figure of Balder was influenced by that of Christ. The Danish historian Saxo Grammaticus (c. 1200), however, depicts him as a warrior engaged in a feud over the hand of a woman.

https://www.britannica.com/topic/Balder-Norse-mythology

The association of the Rune Jera with fertility comes from its cosmic connection to the God Freyr, the ruler of Álfheimr. Freyr, the brother of the well-known Goddess Freya, is the God of fertility and peace.

https://www.zoryawellness.com/jera

How this associated to Greek Mythology:

This has the same connotation as the story of Aphrodite and Ares - the goddess of love and the god of war. Kind of intermingled with Adonis.

Pagan mythology is simplified and doesn’t have extra tidbits to read through, in a way, as opposed to other mythological tales.

In the above link, there is actually sound and valid information about Jera. Runes can be used in Tarot as well. There is a warning on there that says “Do not use Jera to speed up the cycles” because it won’t work, ect.

Jera can be used to heal or to guide one in the right direction of spiritual healing. Just as the 12th house is associated to spiritual healing. It can also to reset a cycle.