Jun Duan is an OC who appears in Bonds Left Unbroken, a Professor Layton AU fanfic wherein the Laytons adopt both of the Bronev brothers.
The older brother, Desmond, first bumps into a teenage Jun in the coastal town of Rooston when searching for a Targent base. Desmond discovers that he is a Targent trainee from his black sunglasses and a tattoo on his arm. Jun agrees to take him to Targent's training centre, the Roost, on a nearby island. On their way there, Desmond sprays some fruity cologne to cover their scent. Jun comments that it smells like a 'fruitcake'.
Once inside the base, Desmond partly discusses his plans to shut down Targent. Wanting to help, Jun suggests he goes undercover and accompanies him to training classes. Desmond recognises Jun's fencing instructor as his old school friend, Mira Sharpace. Just as Desmond fears Mira will reveal his identity, Commander Falcon, leader of the Roost, arrives to retrieve a 'dissident' from Mira's class. This turns out to be Jun. Much to Mira's protests, he is dragged away to be tortured with poison. Mira makes a deal with Desmond to save her students.
Desmond rescues Jun from a laboratory below Commander Falcon's headquarters. He reunites with Mira to free some of the other cadets, but they are intercepted at the docks before they can escape on Raymond's submarine. Commander Falcon (aka- Grace Millar) realises Raymond is her old friend and allows them to leave. She even sends her pet falcon after them with an antidote for Jun.
Despite Jun's wishes to save the remaining cadets, Desmond sees him as liability and doesn't let him accompany him, the pregnant Mira and Raymond back to England. Instead, Jun is given a new alias, 'Dodger', and he is sent to an Irish boarding school.
Its years later when an adult Jun encounters Desmond again, picking him up after Raymond's death at the Infinite Vault of Akbadain. Desmond first believes he has been captured by Targent, but Jun reintroduces himself as Agent Dodger and explains Desmond has been arrested by the intelligence services for his crimes as Descole. However, Jun arranges for Desmond to lay Raymond to rest in Stansbury. Jun accepts Desmond's promise to atone and lets him escape.
Desmond sticks to his promise, teaming up with Hershel and Co to peacefully secure the Azran Legacy before Targent. He meets Jun once more whilst shopping for supplies in London. Jun shares their plans to liberate the Targent-occupied Azran relics and their training bases. He and Desmond discuss Mira's daughter's father, Ryan Herring, before going to help apprehend the 'Targent reprobates' Inspector Grosky is after. While Desmond the others go to find the Azran eggs, Jun vows to watch over Mr and Mrs Layton.
During their adventures around the world, Desmond and his companions receive a message from Jun to say Mr and Mrs Layton are safe. The old couple are in fact captured by Targent. Being a Targent mole, Emmy lied about the message and was responsible for the missing the Azran egg. After this revelation in the Nest, Bronev and Emmy take Luke and Aurora to the Azran Sanctuary. With their lives as well as their parents' on the line, Hershel and Desmond are forced to stay behind at the Nest... until Jun bursts in to help them free Mr and Mrs Layton. At Desmond's request, he takes the Laytons safely back to London. (This is detailed in a BLU Bonus Episode, Making Ends Meet.)
In the end, it appears Desmond and Aurora have not survived the fall of the Azran Sanctuary, but Jun and his team of agents pull them from the ruins. Jun offers to restore Desmond's memories when he wakes up with amnesia. Desmond accepts, adopts Aurora and starts working alongside his brother Hershel at Gressenheller University. He doesn't seem to remember Jun, but he is finally happy.
Jun may cameo in future Bonus Episodes.