The term Companions and Pets refer to the dream world creatures domesticated or tamed by Skarajin in Sonala Ko.
Pets cannot be claimed for more than 1c. Upon leveling up pet and evolving it, grants Companion MYO that makes it into a Companion character that is bound to the Player character on the masterlist, that can be claimed for full coins.
Companion design rules are intended to be very loose and the given species may be interpreted by the player however they want.