Mio-la-mon require Stamina to be summoned, use Abilities' and Battle.
Each Pet has an unique Ability and most can use Ultra Abilities as well.
Most Mio-la-mon after being summoned have abilities that it can use.
Most Abilities will cost (-1) Stamina for your Pet.
Using your Ultra will drain your Mio-la-mon (Stamina -3)
Using your Life Abilities will drain your Mio-la-mon (Stamina -3 to -5 depending on ability)