The 17-year-old is close to making a first-team breakthrough at St Andrews, just 12 months after arriving in England from his native Ghana.
Lee Clark has been so impressed with Arthur's development that he has fast-tracked him into his senior side, and could feature for Birmingham in Friday's Championship clash against Crystal Palace.
Arthur's progress hasn't gone unnoticed, though, with a trio of Premier League clubs considering an attempt to lure the youngster away from the Midlands.
Gunners boss Arsene Wenger has been credited with an interest in taking him to the Emirates Stadium, while Chelsea owner Roman Abramovich is also thought to be monitoring the player's situation.
Reigning champions Manchester City complete the three-way transfer tussle for a player that is yet to sign professional terms with Birmingham, which raises further questions over Arthur's long-term future.
"Koby is an amazing young talent," confirmed Saif Rubie, who represents the promising striker. "We are looking to do the best thing for his progress and they are looking to secure him to a professional deal."
Birmingham chiefs will hope that the Arsenal, Chelsea and Manchester City target commits his future, or else they risk losing Arthur for minimal compensation if he decides to leave St Andrews in the summer.