Having fled back during the Dragon War, Ahgroheyv returned to the Throat of the World to escape from his own brethren and the ancient Nords.
The reason for the conflict with the dragons is his love of power and excessive desire for power not only on his territory, disobedience and strength, which greatly embittered the dragons envious of such things. He was hunted by rivals, as well as rebellious mortals.
Wounded and weakened from the battles, he prayed to his Akatosh father, but Kin responded. For the sake of his salvation, he was given the form of a man, and in return he gave her a promise that he would help mortals in their hour of need. So the goddess turned his dragon shell into a stone sarcophagus far away in a cave and Ahgroheiv plunged into a thousand-year sleep. He was destined to wake up during the birth of the last dragonborn.
He broke the stone shell from the inside - the former shell of the dragon that protected him from the external environment for many millennia, and found himself in the world already a man, although Dovakin could have been several months old at that time. Ahgroheyv spent some time learning to use the weak human body again, and the placenta became stale and looked more like a poor man's clothes. A few days after his birth, he reached an unfamiliar monastery - High Hrothgar. There, not very old Greybeards took him for a mute tramp or a cripple and took pity - they let him in and left him as a servant.
He performed various menial work and simply kept silent, fearing his exposure (although he was absolutely similar to an ordinary person - scales and horns began to grow years later - these are the only changes in his body, he does not succumb to aging and diseases, because he was, as it were, "preserved" at the time). This life lasted for about two years, until it became clear to him that Paarthurnax was interested in a strange servant and demanded to meet him. Ahgroheyv had to deceive the monks who sheltered him and run from High Hrothgar down to the people.
So he ran without taking apart the road along the snow-covered slopes until he came across a nearby village.
People also sheltered him. Then he spoke for the first time in the human language, in which the Greybeards communicated with him, which he learned very quickly, but only orally. The only thing that is still not under his control, even after three decades of living among people, is writing. His handwriting is more like the scratches of a bear's claws on pine bark, which he himself jokes about, hiding a deep knowledge of the dragon language.

The thirst to learn new things and the fear that they might still be looking for him, now forced Heyv, as he presented himself to mortals, hiding his true name, to wander around the villages for several years until he completely humanized - the imperious dragon character quickly changed to patience, intercession and fearlessness - the dragon's soul succumbed to the blessing of Kin. He had to see a lot of good things towards himself from those whom he had previously enslaved and did not consider their lives to be something valuable, which made a great impression on him. It was also at this time that he saw the children for the first time.

One day he was lucky to get to Whiterun, where he introduced himself as a native of the village. Heyv was not afraid of any work - he chopped firewood, helped in sanctuaries (his connection with the Kinaret temple was especially strong), worked in a blacksmith shop, hunted, and was engaged in construction. But working with animals on the farm simply did not give in to him - the animals sensed his dangerous dragon nature and behaved strangely, and the horses he tried to approach froze with fear or started away only when they saw this man.
The usual work was not hard for him - he was superhumanly strong and agile, which was noticed first by the guards, and then by his Colleagues. It was from this moment that his service among them began, and then a small part-time job for the local government - the desire for prestige and wealth played well in favor of his dragon ego, in which he had success.
The relationship between him and his Companions was neutral - the dragon perfectly sensed the different essence of some of the mercenaries, and they, in turn, felt the same strange feelings for him. But this did not prevent them from sitting at the same table at another feast or relaxing in a tavern - they simply did not ask each other about it, as long as no one brought each other problems.
He lived under such patronage for about a dozen years. He has acquired connections, comrades, reputation. But the main achievement that he considers for himself is access to the Heavenly Forge, where he once showed one of his dragon talents with might and main - Heyv forged armor and weapons for himself, based on Nordic motives, as well as from the rare remains of his fellow dragons, as a reminder of the distant past, his essence and an oath known to him and Kin. On that day, the Heavenly Forge was ablaze with scarlet flames from the spray of dragon's blood, with which Heyv generously stained the coals.
He also explains the horns that have grown during this time as a decoration on a diadem (he had to forge something similar in an ordinary forge before that, which would frame the bases of dragon horns).

In order to expand his influence and glorify his Colleagues in Skyrim, he was voluntarily sent on a long trip to major cities, where he did not stop for a very long time.
In Winterhold, he was overtaken by shocking news - Helgen Keep was burned to the ground, and soon Dragonborn absorbed the first dragon soul.

A hunter who is bound by an oath must fulfill his promise.

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