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|“||Sometime in the future...there will come a time when you must make a decision. When you do... I pray that you remain on the side of mankind.||”|
—Go Gun-Hee to Jin-Woo Novel 201
Despite his immense power, his body has become weak due to old age, making him incapable of fighting. It is stated that he gained his powers later in life, too late for him to use it to the fullest. This is why he had to take medications often and his doctor was always worried that his heart might fail due to certain ranges of emotions such as excitement. It is noted that all the guild masters are afraid of him.
Gun-Hee was a tall man with a body of that a pro wrestler. Despite his huge structure, he was an amicable man to those he favors. As a result of old age, he has gray hair and a wrinkled face. The novel describes his voice as “that of an old man, with a slight baritone timbre, deep, but not dark.”
Go Gun-Hee has an honest, open, and righteous personality. He appreciates people with good moral and shuns those whose only aim is personal gain.
He shows this appreciation to Sung Jin-Woo on occasions such as when Jin-Woo said that he'd rather fight monsters, did not take anything from the A-Rank dungeon of Hunters Guild and when Jin-Woo, a person in love with fighting, would rather stay behind for his recently cured mother than go with the 4th Jeju Island Raid Party.
Gun-Hee was once one of the most powerful hunters and it was likely because he was a reawakened hunter. This was revealed after the Ice Monarch killed him. Gun-Hee was actually one of the reincarnated Rulers but because the human body still can't cope with the strong powers brought by Rulers, the full extent of his powers was not shown.
On the last timeline, Jin-Woo gave the Holy Water of Life to Gun-Hee to cure his illness, but his condition became critical again 10 years later. This time, Gun-Hee refuses Jin-Woo help and died normally of old age. Before he died, Gun-Hee requested to Jin-Woo to show him his past memories of the ancient timeline. After receiving them, Gun-Hee passes away satisfied.