Mana vortex
The mana vortex is a building that may be built in the dungeon. It instantly gives an entering hero double their maximum spell points once per week.
Only one hero per week can double their spell points.
Tips
The Vortex will first try to give extra spell points to any Garrison Hero. Remember this, or you might lose the bonus when you need it the most.
For some strange reason the AI never builds them...