The Raven Queen - Mistress of Death

The Raven Queen was once a minor goddess and lover to Baldur, however when Baldur with her help defeated the Primordial of Chance and took up that mantle of power. He cast aside The Raven Queen seeing that there was an outcome where she would turn on him. As is often the case, even for the gods, attempting to alter his fate was the cause of it. She felt jilted and betrayed and began to plot revenge. Knowing the success that Morpheus had in stealing the sand of Dream she hatched a plan. She went to the Endless, to the realm of Death at the edge of the multiverse. There she stole Death's scythe and returned, she meant to kill Baldur permanently with one of the few items capable of ending a god. She managed to lure Baldur from his domain and only succeeded because he had not fully realized his power and because she had helped him lure the Primordial with the same power. Death however was more attentive than Dream and noticed the loss of their scythe. The Raven Queen's first swing took off Baldur's right arm and her second took his left leg at the knee. Before she could deliver the coup de gras Death arrived halting the swing that would have taken Baldur's head. Death was furious with the goddess but did not unmake her as was expected her punishment was to much more through. She followed Dream's example and made The Raven Queen goddess of Death but unlike with Morpheus Death wanted to shape her Goddess. So she killed the memory of the goddess and remade her as The Raven Queen her previous life and even her name dead and unknown to all even the other gods who had known her. Death went further though seeing what the wars of the gods and their pursuit of power had wrought she would humble them and remind them of her fundamental power. She had been too lax and the gods had taken advantage creating immortals to cheat Death. So Death decided that the prime material plane was mortal. The gods and other immortals could exist there but can also be killed there and although they retain the power of creation the making of new immortals was now impossible on the prime plane.
As for Baldur the god of chance, the maimed god, the mad god he could not be healed for the Scythe of Death kills all it cuts. He ran from the goddess who was once his lover and returned to his domain. There he finally bridled his new mantle and with it began to search for a way to restore his limbs and gain revenge on the one who took them. Made more difficult by being unable to remember her her memory of her killed by Death. He went slowly mad as he explored probabilities and none led to his goal. It is believed he is ensconced in his domain still searching for a way to restore himself.
The Raven Queen became Death's champion, opposing mortals seeking immortality and ensuring the natural progression from life to death. It is said that she appears to escort heroes to their appointed afterlife and that her servants escort ordinary people but all ensure that the soul arrives at it's gods' domain. The Goddess of death does not have large followings but all venerate her hoping to ensure that their soul reaches it's desired plane.