World Boss is a permanent Mana Storia event. Each hero will be able to battle Boss Mordath once a day. Damage dealt is computed each turn and the player will receive a Grid reward (varies depending on the total damage dealt) at the end of the battle. There are some quirks in battles against Mordath:
- Mordath increases his stats every turn.
- Mordath's element changes randomly among the 9(nine) existing each day.
When the event resets, players who are ranked as total damage dealt will receive extra rewards.