2 discrete generation. 3 generation left over

In the temple of the ancestors, alternation dominates. Make sacrifices. The blood is mixed. Hybrids

Once there was a society that prized alternation and sacrifice above all else. Every 2 or 3 generations, a new generation would be born to take the place of the old. This went on for many, many years, until there were only 3 left.

The oldest of the 3 was a very austere and serious individual. He refused to make any sacrifices, and he strictly enforced the rules of the temple. He refused to let anyone else take the place of the ancestors.

The second oldest was a bit more lenient. He allowed sacrifices to be made, but only if they were mixed with blood from the third generation. This was to create hybrids, which would be the perfect sacrificial candidates.

The youngest was the most twisted of the trio. He wanted nothing more than to take the place of the ancestors and rule over the temple. He was willing to make any and all sacrifices, and he even mixed his own blood with those of the others to create even more hybrids.

Ultimately, the youngest was the one who took over the temple and became the new generation. He continued to make sacrifices and enforce the rules of the temple, until the day he died and the cycle began anew.