Mana and Stamina are very similar in that they are both resources that are consumed through the use of abilities.
Most physical neutral abilities will cost Stamina, while most neutral energy based abilities will consume Mana. There are also many moves which will consume both.
In order to get the most benefit from both resources, it is recommended that you balance your monster’s moveset in order to use up both resources and have moves that only use Stamina in case you are low on Mana or vice versa.
Stamina is recovered every second your monster is not actively performing a combat ability. Mana is recovered through the use of the Recharge base ability, which recharges Mana every 0.3 seconds while active. How much Stamina or Mana is recovered each time is dependent on your monster’s Stamina Regen and Mana Regen stat.
Mana can be recovered faster than Stamina, but it makes your monster vulnerable for a short time. Stamina can be recovered without putting yourself in danger and also recovers while recharging mana. However, Stamina is used up by the base ability Dash, meaning that without Stamina, your monster won’t be able to dodge incoming attacks.
Monsters do not regenerate Stamina while knocked down, which means that knocking down an enemy is a big advantage since your Stamina will regenerate while their Stamina will remain the same.