He lives in Bilibin's palace with his haughty wife Lady McCoy and constantly balances the needs of his people against pleasing her. He commissions her personal palace to be built from lumber from Kolima Forest, but this angers a tree spirit named Tret into putting a curse on everyone at the nearby village of lumberjacks named Kolima. With everyone in a panic, McCoy immediately halts construction. His concern is great enough that even when the group of young warriors led by Isaac agree to help out by battling the source of the curse early on in Golden Sun, McCoy, fearing for their safety, disallows them from crossing the barricade he had set up between Bilibin and Kolima. If Isaac returns to Bilibin after completing the Kolima Forest dungeon, Lord McCoy will acknowledge their achievement, thank them for reminding him of his duty as lord of the lands associated with Bilibin, and offer the party one of four rewards.
As of Golden Sun: Dark Dawn, Lord McCoy has become king of Bilibin, which has become a country, although it is rumored that the queen is the one in charge.
- Lord McCoy appears to be the only character encountered within the series to have a surname, whereas all other characters shown are given only first names. Granted, simply because McCoy is used with the prefix of "Lord" does not mean that this is in fact his last name, similar to how Lord Babi was known simply as "Babi" before he became a Lord. What is strange however, is that his wife would take his first name when they were married ("McCoy" being a strange first name to begin with).
- He is also unique in the fact that he is depicted having a stereotypical real-world Scottish accent, although he is not unique in having an accent, as the people of Xian also speak with unusual mannerisms. Also, the fact that his accent is Scottish is entirely trivial, as the Japanese version simply has him speaking in a crude and unrefined manner (similar to Garet).
- It is possible the story of Lord McCoy and Kolima Forest is loosely based on Shakespeare's Macbeth; in both stories, a ruler begins to neglect his people, the ruler's wife is the one who edges him on, and the forest ends up "marching" upon his city; though in the case of Macbeth, it is a figurative usage that the leader takes as literal. This would also explain the usage of Scottish surnames in a region based loosely on Russia; McCoy is similar to Macbeth, and it also explains why his wife isn't given her own name, but rather shares his.