Visitors from the east were discovered on an ordinary patrol day.
A squad of Bloodline sentries responsible for the eastern defense line was making its routine inspection of the dried-up riverbed below the hills when they noticed a mark in the middle of the riverbed that should not have been there.
It was a straight groove, about half a meter wide.
Unlike the curving gullies formed by wind or water erosion, this groove was geometrically precise, stretching all the way from the eastern horizon to the foot of the hills before coming to an abrupt stop.
A sentry crouched down and touched the inner wall of the groove with his fingers.
Cold, hard, faintly reflective.
When he drew his fingers back, they were coated with an extremely fine layer of metal powder.
The news was quickly sent back to Deep Sun City.
"Not green."
The chief stood up and stopped the warriors, who were growing increasingly bellicose.
In his mind, he could not help recalling the first chief staggering toward a neighboring community on that first cold night.
"Cold. Together. Warm."
That memory was so clear, so vivid.
So much so that when this generation's chief faced unknown visitors, he subconsciously made the same choice as the first chief.
"The influence of collective memory on decision-making patterns."
Ron marked down this observation in his notes:
"That choice made by the first chief has already been encoded into the underlying logic of Bloodline Civilization."
"It is not merely a memory, but a kind of... cultural gene."
When the visitors from the east finally appeared, the Bloodline warriors saw a lifeform utterly different from themselves.
It was a gathering formation made up of a dozen or so metallic units.
Each unit was about two meters tall, its shape somewhere between a human