One of Julian Gollop‘s earlier games, and one that was based on a card system he created as a boy.
Chaos: The Battle of Wizards is a turn-based tactical combat game for up to eight players.
Each player takes it in turn to issue commands and choose and use spells against each other. If you’re playing on your own the computer AI steps in and gives you a battle.
Chaos might not look like much now, but as an early example of tactical, magical combat systems it was one of the first and one of the best.