His father chose to return to earth because even if they were a vampire and have an almost immortal body they are still aging and his father was already old at that time. Although the tournament was not complicated it didn't end easily. It lasted for almost a million years that even he, a vampire, aged by a lot. He was the weakest of the three which is why he chose to just stay away from the fight and decided to go back.
Then after going back to earth his father found out that the previously almost extinct humans had begun to take over the world and there was not even one vampire who existed except him. Based on the history that his father told him it all started over a million years before they transmigrated. Legends have it that vampires drink human blood but they don't really need it to survive but as time passed by because it was the most delicious delicacy for them they started relying on drinking human blood to live.
From then on the human population started to decline and gradually reduce over the course of time. Thus their main source of food started to decrease and because they have started relying on human blood to live they couldn't control themselves at that time and they started fighting each other until Vampires gradually reduced to the point that it has almost gone extinct. Their previous number which was almost a million was nowhere near their population at that time as their number did not even reach 4 digits.
At that time there were also some humans who can fight with some vampires but they are not strong enough to overthrow them which is why they started hiding which made the vampires cannibalize their own kind. This also made the vampires even stronger because they absorb their kind. Because vampires consist of more nutrients than human blood they then started to grow stronger and stronger than they even forgot the humans. This is the reason for the decline in their population and as they yearned for more power they didn't realize that their kind didn't even reach 4 digits in number.
But due to this, vampire races have reached the peak of their development which is why after the transfer into the Ravaryn world all vampires were included, and not even a single one of them was left on earth. Which is also the reason as to why Ivan and Vladimir were curious as to why Vladimir did not get included in those vampires who got transported in Ravaryn. This made their curiosity reach its peak but even Vladimir didn't know the answer himself. He did not even have a single idea about the so-called Ravaryn. Not even him who had lived for a millennium and reigned all over the Earth and the vampires know.
Ivan speculated that after the transfer humans have reigned all over the Earth because of the sudden disappearance of their race. Ivan's father was also clueless about what happened even after he went back to Earth he didn't even know that Vladimir was still alive. Ivan thought at first that Vladimir was one of the three vampires that came back from the Ravaryn world but because Vladimir didn't even know what happened back then he rejected his thoughts.
Meanwhile, Vladimir was confused because he knew that the most delicious thing for them in the past was the blood of a human and they can really get some nutrients from it. It is also the same if they eat their own kind because Vladimir even eats the body of his family when he got imprisoned. This is also the reason for his sudden strength because he had eaten his family at that time. And when he slaughtered the previous ruling kingdom he also ate them, thus, he became the Lord of the vampire because he had overthrown them himself.
At that time it was a taboo to eat your own kind because they needed to digest them. Even a newborn vampire needed to be digested for a thousand years but he was different because of some unknown reason. He was the strongest at that time because he could eat his own kind almost unlimitedly. And as he ruled over the vampire race he needed to hibernate but even a thousand years was not enough to digest all vampires he had eaten which is why he decided to hibernate longer and this is also the reason why he was asleep for so long that even the course of history had changed or he thought so.
Vladimir already speculated that the vampires in the past were not the same as the vampires before and he also found out that even after absorbing their own kind they only gain an ample amount of their enemy's power. It's different from the vampires in the past who could absorb all of the powers of their enemy, they just needed time to fully absorb it. But for the previous vampire they might think that that the vampires in Ivan's father's time were much more powerful than them because they can absorb vampire blood and digest it easily but what they didn't know was that the vampires at that time were a lot weaker than the vampires in Vladimir's time.
In his time it is normal for a vampire to live for millennia while in Ivabn's father's time it was different. Even he who was considered as the strongest among their races did not even last for a millennium and he was already so old when he went back to earth. Although it didn't show on their looks their life expectancy gradually decreased and it is only limited. This is also the reason as to why Ivan's father was already dead.
Then his parents met each other and gave life to Ivan. But after just a hundred years his father died. Although he won something that could make him even stronger because he was one of the strongest people in the universe. Although he was the weakest in the three he was still one of them and at least contributed to the battle.
The battles between each universe were on a different scale which means that their rewards were the same. And unlike before they even received rewards that can be used among themselves and not randomly appear on the Universe itself. But of course, it was only limited and the rewards will only be in every five battles. There will be three rewards and one for each of them. But unfortunately, they were defeated and they only got the consolation prize which was also stated by the system.
Each of them had one different reward based on their contribution. So Ivan's father thought that he would be placed first and his reward would be the lousiest one. The ranking was hidden away from them by the system which is why they did not a group but based on the three of them it was very obvious that Ivan's father was the one who contributed the least.
But after the two stated their rewards Ivan's father who can be said as a genius knew that the system had different parameters where it based their contribution. When he compared their rewards to himself he found out that his rewards are not the lousiest at all. Ivan's father speculated that it was not only based on their damage to the enemy but also the damage they have taken and because in every fight he was already on the verge of death his contribution rose.
Thus, Ivan's father tells them that he received a different reward. He made it so that they would not try to get their hands on his reward. Although they have fought as a companion for centuries he still knew that they would do anything for them to become stronger. This is their nature, especially if they don't reach their stage. Even Ivan's father was the same but unlikely he gradually lost his interest in those kinds of things after he saw how big the world really is.
This is why he chose not to come back to Ravaryn and continue the journey to Godhood. Although he had received something that could make him stronger he did not use it and instead gave it to Ivan, his son. But before that Ivan's father went back to earth and met his wife who bore him. And due to his parents being a vampire and a human he became half-vampire which made him different from vampires. His father did not have any other children before he died which made him the last bearer of their bloodline.
He was the only one on Earth who had vampire blood and at that time humans have become lenient and lazy thus they forgot to strengthen themselves and they also forgot about the vampires. The history about them became legends over the course of time that they did not bother to strengthen themselves anymore which was their natural nature.