Tactical battles system ALA Fire Emblem and Advanced Wars

[Life Swordsman]

Hello again, still n00b here, so sorry if I do anything to get in trouble, but I need helpin trying to make a battle system like in Fire Emblem and Advanced Wars. My main consern is how to have multiple charaters with just one character set-up

EX: multiple "Warrior" Units that level up seperatly, but start from the same character and don't use multiple characters slots (sorry if I don't make sense)