Mana (also known as MP, which is short for Mana Points) is the Resource that many Classes need to be able to cast most of their Spells.
Just like healing Health, a unit's current mana can be restored in various ways.
Base Mana regeneration
Every class with Mana as their Resource has a base Mana regeneration stat that passively restores Mana every second, this value can further be increased with the help of Gear.
Every Class in Arena of Kings has a basic attack that not only deals damage, but also returns a certain amount of Mana.
Weaving in enough basic attacks between your Spells and Movement is an important factor to increase your maximum DPS and Mana Regeneration.
Most classes can also restore their Mana through certain spells:
Meditate is a Common Ability for all classes. Press Z (Standard keybind) to begin the 1 second Meditating cast, which buffs you for 10 seconds, restoring Mana to casters and Health to non-casters. Meditate ticks every 2 seconds and the amount restored is increased every tick. Meditate ends upon taking damage, moving, or receiving a new debuff.
Gear & Stats
1 Point of Intelligence will provide 1 extra Mana.
1 Point of Wisdom will provide 2 extra Mana and 0.1 Mana/sec.
HUD Mana bar
Mana of the selected unit is displayed in the HUD as a blue bar at the bottom of the screen.
Over-head Mana bar
The Mana bar of all Characters is also displayed right above their heads, below their health bar.