Thistle

シスル

The mage responsible for creating the dungeon on The Island.
Thistle is regarded as irrational and not inclined toward reasonable conversation. He appears single-minded in his devotion to King Delgal and the Golden Country.
He has a habit of inflicting injuries on himself whenever he feels frustrated. He has scratched his head until it bled and frequently chews on the tip of his thumb.
As the lord of the dungeon, Thistle holds significant power over both the dungeon's structure and the monsters that inhabit it. His lifespan has also been extended by the dungeon's power. He has altered the dungeon's structure on multiple occasions, most often causing it to open a hole in the ground to both eliminate enemies and allow himself to escape. Regarding monsters, he typically calls them to his aid or instructs them to act (for example, tasking the Red Dragon with finding King Delgal). He seems to favor using small dragons nicknamed 'the magician's eyes' to sense and alert him to changes within the dungeon.
The English translation, published by Yen Press, adapted his name to "Sissel". In the official Japanese manga, he is named "Thistle".