Gods of Sparta factions
The game is based on 4 card types. There are 3 unit factions: Olymups (Zeus, Athena and some creatures), Underworld (Hades, Cerberus, Minotaur...) and Humans (Achilles, Hercules, etc.) and some items that the units can equip.
Olympus will have a bonus when fighting against Humans. In mythology the gods of Olympus always had control over human fate.
Humans will have a bonus against the Underworld units. In myths, greek heroes often defeated the monsters and some even went into the world of dead to do some quests.
Underworld unit will have a bonus against Olympus. This will make the game fairly balanced. A single unit can be extremely deadly against one opponent and completely useless against the other.
The units will have a single number for attack, defense and energy. But there will be different special abilities that can increase or decrease that during battle. There will also be items (artifacts) that modify attack and defense. For example, here's a sword I drew in InkScape:
