Surprise! Explosion!

Since ancient times, dragons have been the symbol of absolute strength. This image has been the same for a lot of worlds over the past eons. However, everything changed after the appearance of humans.

With their uncanny wit and their strength in numbers, the absolute being that reigned at the top was dethroned and replaced by them. Humans then became the strongest race to have existed since then.

Later on, other humanoid races appeared, which were all a lot more powerful than normal humans individually. These include elves, dwarves, beastmen, and such races. Among those races, the one that was arguably the strongest combination was that of a human and a dragon, a dragonkin.