Relic
Mage's Cataclysm Engine
Legendary
Effect
Heroes gain 50 Magic.
Whenever a 
Mage casts, they inflict Burn and Frost on all enemies in their range equal to 20% of their Magic.
Where it drops
- Auction House (Legendary Relics)
Other Legendary relics
Questions people ask
What does Mage's Cataclysm Engine do in Guildrun?
Heroes gain 50 Magic. Whenever a Mage casts, they inflict Burn and Frost on all enemies in their range equal to 20% of their Magic.
What is the difference between a relic and an item?
Items are equipped by a single hero and take up one of that hero's slots. Relics apply to the entire guild and do not use slots. That makes relics the stronger of the two when a build starts coming together.
How do I increase my team size?
Harmony Crystal raises it by one, up to five. So does each of the fifteen Mandate relics, but those require finishing an objective first, like dealing 15000 auto attack damage or applying 30000 shields. Pick the Mandate that matches what your team already does.