Reborn: My Apocalypse Bunker

Shane Shaw is reborn on the day the Lee family forcibly buys his land. He gets Black Dragon Ridge in return, but secretly knows a top-tier armory is hidden underground. He activates an infinite subspace system, hoards supplies, and upgrades his doomsday fortress. When the extreme cold snap arrives, relatives blackmail and the Lee family attacks. Shane Shaw strikes back, building a safe zone in the Ice Age apocalypse against his enemies from his past life.