The name of the giant, also known as a Treant, was Nyx.
Nyx was the first child of the World Tree.
The World Tree was born in a desert, destined to die. At the time, the World Tree was the size of a sapling and was indistinguishable from a tree with no will.
As a survival instinct, the tree gave birth to Nyx, who appeared like a normal human child but greener.
Upon seeing his dying mother, Nyx began hunting for food.
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They always had it hard.
One day, a bear-like creature covered in chitinous armor came and began attacking the tree.
Sadly, Nyx was out hunting in the wild.
While the creature was attacking the World tree awakened her will through her pain and wounds and began telepathically screaming "Nyx!!" while screaming and crying.
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After hearing his mothers cries Nyx rushed back and saw the creature eating his mother.
Nyx became enraged and jumped on the creature while forming claws over his hands.
He trashed the eyes of the creature and hit a part of the chitinous armor away with his claws.
Nyx eyed the vulnerable flesh and bit it.
As the creature was screaming it tried to throw Nyx off his back.
As for Nyx? He tore the creature's flesh with his fangs and dragged with his claws the organs out of the creature.
The vocal cords of the creature tore as it was screaming loudly from the pain. Even after the death of the creature Nyx kept defiling the corpse.
While he was doing that he heard his still crying mother. Nyx ran to his mother and said with soothing words "It is over, you can sleep, go to sleep...."
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After making his mother go to sleep he said this "One day i will make you reach the peak and make you never feel pain again"
But this promise will be broken in the future....
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As thousands of years passed the surrounding desert had changed to a forest through the influence of the World tree, but as mother and child grew stronger they began attracting attention from the whole world. They were also reaching the stage close to godhood.
This infuriated the other gods.
After this there were many wars and to fight, the World tree began birthing new species. There came the elves, dryads, faeries, forest spirits.... There were not only soldiers but plants like flesh eating plants, peashooters, vines who would attack non-residents of the forest....
As for Nyx the Treant he had grown to an unbelievable size. He also had many names like the forest Titan, one man army, living siege, blood giant...
The abilities of Nyx had also grown. He could shape his body to his own will, he could grow the species of plants that his mother birthed over his body.
His mother had a domain ability. This could be seen as lightly but every plant in the forest was part of her domain and the domain kept growing together with the growth of the forest. She could shift the forest and the lands under it and because of this the forest was like an undefeated fortress.
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After some time they reached godhood, the peak of every organism, but this enraged the other gods further. All races and many other gods began organizing Holy Crusades against the World tree and The Treant. This was also the greatest challenge Nyx and his mother overcame.
After this war Nyx got more titles and this time also known among gods. The Berserker, The God Killer, The Undying, The Demon and The Terror Tree.
Nyx was seen as a demon because he always kept no captives and even slaughtered every begging soldier to god. He even put the evil gods to shame with his actions.
Contrary to the World tree who was too kind to even execute captives.
This war was won by Mother and Child. The remaining gods and armies began retreating in terror.
Sadly at the end of the war Nyx was fatally injured and dying and because of this the World Tree sacrificed her godhood to keep Nyx alive.
The World tree would never recover from this sacrifice and would be reduced to the state of demi-god but she didn't care.
For her Nyx was everything.
After this procedure the World tree built a tomb under her own main body and put her injured child inside and closed it up to never be opened for a long time.
As Nyx slept he gradually recovered more but he would keep going for thousands of years.
Now that her Child was gone she could only hope for help from her other children.
The gods themselves were terrified, injured and exhausted in the last battle and because of this they did not attack the vulnerable World tree but this would not last forever.