"Amazing you will be!" Hephaustus looked delighted. He moved forward and started sliding his hands over Derrick's equine body. The man was surprisingly strong, the pressure of his palms reaching deep into the horse hide. Derrick grunted, but it actually felt good, like the firm massage he had gotten from the boys. An inner warmth started to build as the blacksmith circled him, slowly increasing into a dull heat that was still very pleasant. When Hephaustus reached his front the second time, he ran his hands up Derrick's human chest. It was an odd sensation, for his matured body was hairy and well muscled, and he had a light stubble on his face instead of the peach fuzz of a teen.
After the blacksmith's hands had worked up the sides of Derrick's head to tousle his hair, he started all over. The warmth was now a pulsing heat that made Derrick feel flushed. He twisted around to watch the man work, and stared in amazement at what was happening. Where the first passes of massaging had seemed to just create heat, Hephaustus was now leaving a swelling trail of glossy black hide. Derrick could feel his muscles and bones thickening, the ripple of strength that sank deep into his body.
When Hephaustus reached his hindquarters, he reached under and worked on the already large stallion's equipment Derrick had yet to try out. The boy gasped as the warmth swelled into intense pleasure - Hephaustus was hefting a shaft that had emerged under Derrick's belly, turning the pink and black shaft into a massive black organ. His testicles grew taught, then hung heavier. Probably intentionally, Hephaustus took longer here and Derrick shuddered as powerful instincts and hormones coursed through him. He had masturbated before, but this was a hundred times better, a thousand! When he finally came in a thick jet, Derrick's mind closed down for a moment to all but the animal lust and satisfaction.
Hephaustus chuckled and continued around as Derrick recovered, eyes wide and sweating. "Oh, man! That was... incredible!" It took a full minute for Derrick to clear his thoughts enough to realize he was very lopsided. The black side was much thicker and larger than his unchanged side, and he was tilted awkwardly. That was quickly fixed, his legs lengthening and thickening and hooves swelling out. If his first centaur form had felt strong, this one felt unstoppable, like he could kick down stone walls and pull down buildings!
Derrick felt the heat in his human belly and chest and looked down to see his tanned skin darkening to coal black under the blacksmith's hands. Hephaustus grinned up at him, having to stretch up due to Derricks much greater size. "All black, a mountain's shadow! You will be a walking wall of night." Although he had not expected more changes to his human parts, Derrick saw that his muscles were growing along with the midnight skin and grinned. "OK. You're the boss!"
The blacksmith nodded cheerfully. "Yes, I am the boss. Lean over so I can reach your shoulders and head." Derrick did as instructed automatically, flexing his arms as Hephaustus made them ripple with thick, corded muscles like a professional body builder sculpted from ebony. He could feel resistance on his neck, a mane that flowed down his backbone to his equine back.
That must be what the blacksmith was creating on top of his head, the strong fingers pressing into his skull. Derrick had the odd sensation that the top of his head was sinking in, flattening out. He reached up and discovered that was exactly what was happening, the normal curve of his forehead now dropping off behind brows that were very pronounced. "Hey! What are you doing?" Hephaustus was sliding his fingers around Derrick's eyes, and his vision blurred and shifted, his field of view expanding out. At the same time, the boy's thoughts seemed to thicken, slow. He struggled to understand what was happening, confused and starting to get a little scared.
"Easy, boy." Hephaustus spoke soothingly as he stroked Derrick's lower face, drawing it out into a dark muzzle that expanded to fill the center of Derrick's vision. "You are almost done, my fine, handsome boy. Easy. Easy." The calm, familiar voice eased Derrick's fear, thought the confusion remained. Derrick's velvet nostrils flared out, drinking in the rich odors of the pasture, the nearby stallion and the other horses, the human master, his own musky stallion's scent. Calm flowed over his thoughts as Hephaustus finished up and then just rubbed Derrrick's broad head between his wide-set, liquid-brown eyes. "You are magnificent, the largest and most powerful centaur here. You love using your strength, your power to work, to be useful and obedient. You do not need to think of complicated things like numbers and writing and all the other useless knowledge that belongs to a human. You need to know how to pull, to lift, to use that magnificent body and be happy as a centaur worker."
Derrick felt his thoughts thicken again, and became aware of unfamiliar thoughts and memories flickering in the back of his mind. He had never trained in a plow harness, had never pulled a wagon as part of a team, had never mounted a mare. Why did he remember spending hours at heavy labor as something positive, something he enjoyed? Yet even as he questioned those thoughts, he found himself accepting them. Yes, it was very good to work, to pull, to make use of his muscles and mass. That was his purpose in life.
Hephaustus rubbed the massive black creature's had a while longer, feeling the former boy relax, become content. He was an equitar now, a Shire-based centaur with a massively-muscled human chest and the full head of a Shire horse. Magnificent and strong, the most powerful, beautiful centaur ever. The blacksmith grinned as he looked into the huge brown horse's eyes. It was so rare that anyone let him really be creative. This boy would be a treasure for the resort, a hard worker and tourist attraction. He had not wanted to go back to being a teenager - now he could remain a mature male. Hephaustus nodded in satisfaction - he had truly given the boy everything he had asked for and more.
Derrick let his huge arms hang limply from his side, content to stand and be petted by his master. He remembered being human, remembered his family, even remembered most of his past life. However, none of it was important. All that mattered to him now was being the best centaur, the hardest worker, the most powerful and biggest of all.