Gretch is a giant, approximately15' tall, with a jolly and welcoming personality.  He seems to have no powers other than his size.
 

Kevin Matchstick, Kirby Hero, and Joe Phat go to meet Bartholomew Gretch and Isis for some help in their quest.  They are trying to figure out who is behind their recent problems.  Isis helps them, and while they are in a trance, the Sprigginflints attack.  Gretch goes outside while the heroes are still waking up, and battles the small flying evil faeries.  He does well for a while, but eventually they manage to all get him with their venomous bites, and he falls to the ground, crushing Kevin's Edsel car.
 
The heroes manage to get the Sprigginflints to retreat, but Gretch is on death's door.  Kevin tries to use the magic of the Bat for a new purpose--to heal.  He zaps Gretch, and he awakens fully recovered.  Magically (and one might say cheesily) his baseball cap now sports a lightning logo like Kevin's shirt.
 
Later on when Isis visits Kevin in Montreal, she speaks to Gretch via a magic television.