This story will involve sex between humans of both sexes and various aliens of various sexes. Everyone involved is at least 18(or whatever the equivalent is on their planet!)
Inspiration comes from numerous writers including of course Edgar Rice Burroughs, but also as things develop, Robert Heinlein, Philip Jose Farmer and Herman Melville.
***
He could see the light of Napris fading as he ran through the trees. He had to catch the Rokken before first nightfall. If he failed she would not die, but she almost certainly would not want to live. He pounded on, his bare feet thudding on the forest floor, sweat forming a glistening sheen as it ran down his back. The short leather kilt that was his only clothing swung on his hips, chafing his luminous blue skin as he ran.
[[Blue skin? WTF]]
In his each hand he held a spear, long, straight with barbed points. Across his back was a great sword, his image of power among his people, for no one else could handle a blade of such weight with his dexterity.
Suddenly, through the trees he saw them. Three Rokken, one with the girl slung over its shoulder, all three of them running steadily, their lumpen hairy bodies much more effective than they appeared. Even so, he knew he had them now. He quickened his pace, hefting the spear in his left hand as he ran. He was gaining on them. Suddenly he burst into a clearing around a rocky outcrop. They heard him break through and turned, snarling. Without breaking step he hurled the spear in his left hand. It flew though the air to take one of the Rokken square in the chest, driving through its lumpen blue flesh to impale it on the tree behind. The Rokken with the girl, threw her to the ground and the two remaining charged towards him. He threw the second spear and it pierced the creatures throat. It flew backwards to land in a pool of stinking water where it died, screaming.
The final Rokken turned to grasp the girl and flee before it met the same fate as its companions, only to be met by a smashing blow to the side of the head from a stone thrown by the girl, felling it to the ground.
"Quickly" screamed the girl. "First night is almost upon us. We must get into that cave until Mura rises for second day. "
Without stopping, he ran forward, pulling the first spear from the tree like a pin from a pin-cushion, hurling it into the cave the girl had seen. A great roar echoed from it before a huge wolf like creature burst forth. Snatching up the second spear he ran forward and thrust it without pausing into the creature's breast. Leaving the beast in its death throes, he seized the stunned Rokken by the hair on its back and ran on into the cave, closely followed by the girl.
[[WTF?]]
Once inside the cave he paused to take his bearings. The cave ran deep into the rock. Towards the rear was a pool of water, behind which it bent to the right. The water in the pool glowed milky white and steamed gently. There were signs of occupation by the pool where there was a pile of animal bones, but otherwise it was empty. He turned to face the entrance. Just outside was a huge bush. He stepped out and seizing it bent it down to obscure the entrance.
"That should be enough during first night" he said. He turned to the girl, who stood before him, naked as he was apart from her short leather kilt. Her body was firm and round with large breasts and wide hips. He stepped towards her, the Bloodlust rising in his veins, his phallus thickening and rising beneath his kilt. He stripped the kilt from his body, throwing it to one side and taking the girls arms in his huge hands.
"NO!" she cried. "I know the Bloodlust is upon you, but I am not yet ripe and if you plant your seed in me I will be damaged and your soul will lose many levels of advancement.
"I care not," he cried. "I will have you for my sword cannot go unquenched when my blood is high."
"You can take her" said the girl, pointing at the hapless Rokken cowering against the cave wall.
He turned as the girl pointed. The Rokken was indeed female, and beneath the dirt and matted hair appeared to have all the attributes of a Human female.
"I cannot take that! It would be like rutting with an ape."
"No, she said. They can speak and have some understanding of our ways. My father thinks that they are fallen Humans, but because of some great disaster were reduced to living and mating with the great apes. If you plant your seed in her, your offspring will be as Human as you or I because you are a Hero."