I think I posted an early version of Mansbane background somewhere in the forums, but here you are as well:
The origin of the beast
In the Old Days, the First Dark Lord created all kind of creatures to trouble the Children of Ilúvatar. Thus came to be the race of Orcs, Trolls and many other evils that sill exist in Middle-earth.
But his most powerful followers were the spirits he had corrupted and had joined his rebellion against Ilúvatar and the Powers of the West. These were the Úmaiar or Fallen Maiar and they varied greatly in power. The most powerful were the mighty Valaraukar, destructive spirits of fire and rage, but some of the lesser Úmaiar decided to embodied themselves, because doing so they gained power over the matter of Arda. Thus came to be immortal Orc warlords who returned to fight again after being defeated, great wolves full of malice, flying vampires thirsty of Man blood and many others.
This is the tale of one of these incarnated Úmaiar and her firstborn. She chose to beget warlords for the Dark Lord’s glory and be the Queen of them all.
Her true name is lost in legend and tales but what is known for certain is that she was with child when the Host of the West defeated her master Morgoth and she managed to flee and hide. Although she paid a high price for her survival, her skin was covered of wounds that would never completely heal and her spirit was broken.
Her child was born and for years untold they contented themselves with a miserable life, always on the move. But after centuries on the wild, she began to regain her strength slowly, as her son grew stronger, and her hate for the Children of Ilúvatar was fiercest than ever before.
In their wanderings they came to a forest where Trolls dwelt and soon she became ruler of them all, for her son even in his youth was strongest and biggest then any Troll and she was wiser and had powers beyond the reach of Troll-kind. Men living nearby where enslaved or exterminated and the region became known as the Trollshaws.
Those were good times, the Goblin warlords came to her to offer tribute of slaves and gold in exchange of her powerful Troll warriors. But men came from the damned West and they were stronger and their steel swords were sharper. The Troll clan smashed them, but they kept coming. So the clan retreated to the dark caves under the Misty Mountains although some of them remained in the forest.
Then came the rise of the Witch-king in the North and all of her clan followed the call to war. All except herself and her eldest son, for he was bound to her by an oath he dared not to break. At this time she was already known as the Mother of Monsters because she had had some other children over the years, Troll-blooded ones. But her eldest was the most powerful, the most alike to herself, and the only one she called her own kind and so she kept him by her side. He was full grown now. Cunning as a Warg he was, more merciless than an Orc, a natural born leader.
No steel could pierce his skin and no sunlight was too bright for his eyes although he cherished the shadows of night as any other evil creature. Then the Witch-king was defeated and all of her clan perished, but the Misty Mountains remained a safe place. With time, the Goblins increased their numbers and the Wargs roamed the Anduin Vales. The son of the Mother of Monsters went down the mountains hunting and it was then that the entered the legends of the Northmen and they called him Sceadugenga, the Shadow-goer because he attacked always at night, devouring travellers and lonely hunters. Legends of his ruthless and terrible misdeeds and of Angrboda, the Mother of Monsters are still remembered among the Woodsmen of Mountain Hall and other Northmen of the region. Only the mighty shape-shifters dared to oppose him. But soon enough the gigantic bears were defeated one by one.
The last battle against the bear-folk was terrible and bloody. Sceadugenga was severely injured for the first time in his life and on the bear-folk side only a youngling survived. Sceadugenga was taken for death and the youngling went north to the forest and settled there as a loner. But Sceadugenga survived thanks to his mother’s powers and this victory gave him so much renown that all the Trolls of the Misty Mountains accepted him as their leader. It is told even the Great Eagles were wary of his flying boulders.
Her mother did not want him to go to open war against Men or Elves, for she saw in him the future of her legacy and her bloodline and he obeyed. So, they refused the call of the power of Dol Guldur, although they let some of his warriors to join his forces. They both remained a legend for the Northmen in their deep cave decorated with bear skulls .Very few Men indeed had ever seen any of them and survived to tell the tale.
Some years later, a great muster was called and war was declared against Erebor to avenge the death of the Goblin King and seize a dragon’s hoard. Sceadugenga was eager to lead the Trolls to war but her mother claimed they have sworn no oath to the Goblins and it was too risky. She was adamant and no Troll was present in the Battle of the Five Armies.
This brought many ill consequences. The Goblins were defeated and perished in great numbers, so Men began to expand. Sceadugenga was blamed for this and lost the respect of the Troll clans of the region. Then he decided to break the oath to his mother and he went on his own.
Recently he has left the cave and settled in a mist-covered swampy valley near the Anduin river. From there, he has begun to launch bolder and bolder attacks against the Mannish settlements in the area to prove himself worthy to regain the leadership of the Hill Troll clans of the Misty mountains and the Woodsmen are refering to him as Mansbane. Without his mother to stop him, he expects to become a fearsome warlord on his own and a force to be reckoned with.