The brothers are indeed brothers of the same father but the cubs which they laid are actually not exactly 'cubs'. The cubs are MC and ML from a future timeline. The MC is an orphan from 'Earth' whereas the ML is the emperor of their era, the top of the hierarchy in terms of his genes and his/his predecessors' achievements, a Kanta.

The world which they lived in prior to travelling to primitive times was a very advanced world, where due to the evolutionary changes over the centuries, the ancient creatures from the era of dinosaurs can as such, turn to humans. Even trees are able to transform into humans and live for ages; thus, these evolutionary creatures are able to place themselves in the upper stratum of the society. The MC is an orphan from the human world, though much light hasn't been shed into either MC or ML's past. So, throughout the course of the story, you can assume that we're pretty much kept in the dark about their past lives but by the author's short hint and clues, we can definitely uncover one thing, the ML did love MC in their past lives and that's why threw MC into the time-space capsule to survive taking up the brunt of the attack for him (MC). MC took ML's feather with him to the time capsule and this helped in preserving both MC and ML's genome after their deaths, for it (the capsule) to reprocess again and help them out in this process of 'reincarnation' into a new time-line.

Thus, when one of the Kanta Brothers (Bai/White) ate the egg (which was actually the capsule nurturing both the MC and ML's life) and excreted that out, he misunderstood that he might have laid eggs and brought this good news to his other Kanta brother (Blake/Black). And, with this misunderstanding, the two Kanta brothers ended up raising the two cubs (MC and ML).

Also, albeit the... late review (because I had written only half of the review prior to this) I'm really grateful to Amaruna Myu for taking on the job of translating this novel. Since if she didn't do so I wouldn't have come across such a treasure. And honestly, I'm not really good at understanding MTL translations😅😅, but in the novel, MC did find ML's remains in the primitive world, which is a clear indicator that the majority population had already been whipped out in the catastrophe that hit ages ago.. and only the meagre population survived the wipe-out.

Back then when I read the novel, due to some links missing in the Google translated version, I theorised that most probably the capsule (in which the MC took shelter) has the ability to transverse through space-time which made the MC and ML travel back to the primitive era. But, the fact that MC was able to exhume ML's remains after becoming a victim of an earthquake, refutes all the prior conjecture. After reading Amaruna's review I realised this fact that if I were to go by my conjecture, the fact don't add up. Thus, it might have indeed been possible, due to the technological advancements that humanity had achieved, it was bound to get wiped out in a natural catastrophe and the main protagonists were thus, indeed born in the future aka "Primitive era".

Instead of MC and ML coming from the future timeline back to the primitive, I prefer to believe that they are actually in the far future when everything was destroyed because of how the world works and everyone starts over from scratch, species evolution and human development-wise. So rather than the two characters travelling back to the past, I would say they went to the distant future, and that their past selves were well, past.

However, this interpretion is from what I MTLed, which may be accurate. I'm hoping that I'll have a better understanding as I translate the story

I mean.. Yeah he's just a big cub. An adorable cub. 😅 But I really like Louis I tho. The man is so damn heroic. I even cried when I read to the part where he "protected" the MC in both lifes. 😭

For example, where did George come from? Is he actually an egg that Louis and the MC laid? Why did Grandpa Meng never turn into his human form? Will Louis ever get his memories back?