Fine tune an immortal's permanent frozen physical / visual age by adding or subtracting 1, 5, or 20 years at a time.
Children born with inherited genetic immortality that have not been manually age-set or immortality-configured will be auto-aged at each birthday by mod-script until age 20.
Grant, switch-between, and take away one of three types of immortality - standard / non-genetic, genetic, and sterile.
You can, via Decision (self only) or Interaction (self and others):