They lived in nests, sometimes hollowing out large trees to use as a base. They were led by a Brainleader; a super intelligent Kreech that was only born in every 10 generations. The Brainleaders purpose was to guide and support the colony without whom the Kreech would struggle to survive. The lifespan of a Brainleader was at least 10 generations longer than normal Kreech. (COMIC: The Cleverest King)