Companions can be upgraded and equipped with items just like the main character. The arrow keys to the left and right of each character's profile picture can be used to switch between the companions and the main character.
Class-specific items can be obtained, for example, in dungeons of Shadow World, in the Tower or by using the toilet.
Companions' weapons and gloves can be enchanted by the witch with the corresponding spell scrolls.
Barbaric Bert
Class: warrior
If the main character is an Assassin and you give Bert a class-specific 3-attribute weapon, the weapon's main attribute changes from dexterity to strength.
Magic Mark
Class: mage
If the main character is a Battle Mage and you give Mark one of your class-specific 3-attribute items (except weapons), the item's main attribute changes from strength to intelligence.
Clever Kunigunde
Class: scout
If the main character is a Bard or Druid and you give Kunigunde one of your class-specific 3-attribute items (except weapons), the item's main attribute changes from intelligence to dexterity.