Pet

Pet, minion and other affectionate names are given to the creature summoned by caster type monsters or character classes.

Pets of any sort have very varied attributes. In some cases it's as simple as a small creatures sent in large numbers to die horribly while dealing some damage, and it can be a summoned beast that is even more dangerous than the original caster.

A "pet class" in terms of character class is a class that is not only capable of summoning a minion, but is also to some extent dependant on this summoned creature. They would be slightly more frail and deal slightly less damage than other classes in exchange for having a separate unit helping them killing monsters.

The pet is then often used as a tank. If the class has many summons, it can work as both tank, healer and DPS.