Complex sentence: However, they are discovered by the Bergens, large miserable creatures, who can feel happy only after eating a Troll.The Bergens imprison the trolls and eat them every year on a special occasion, called Trollstice.
Split into simpler sentences: However, they are discovered by the Bergens, large miserable creatures, who can feel happy for a moment, upon devouring a Troll. Every year, the Bergens imprison the Trolls and eat them in a special occasion, called Trollstice.