Your favourite character is given 5 years, to prepare for the fight of their life. They can train, get equipment, round up allies, and even pick and set up a home base in which to fight from. Characters are allowed any friend, or ally who the know, or could conceivably hire, or enlist. A king for example could draft all his civilians, hire mercenaries, and get aid from allied kingdoms, and could arm them and fortify his castle. A civilian in the DC universe couldn't enlist the justice league, or the police.