Bronev has grey hair in a rough style. He has a beard and mustache. His eyes are hidden by his sunglasses. He sports a red shirt and over that a blue jacket with a white handkerchief in his left-top pocket. He has very thin legs on which he wears white trousers and brown shoes.
Bronev appears to be bossy and is the leader of the Targent agency. Not much is known concerning him, but he is ruthless towards his underlings, including Leonard Bloom when the two discussed the Mask of Order. He is also very determined in his goals, wishing to utilize the legacy of the Azran civilization.
A man whose identity is shrouded in mystery. Detective Bloom is his subordinate, and he appears to have some sort of connection with Descole, but even this fact is, at present, unclear. He seems to be looking for something related to the Azran civilization...but what?
Leon Bronev was an archaeologist who specialized in the Azran civilization. He lived with his wife, Rachel, and children, Theodore and Hershel, in a village. When his children were still young, Targent learned of his findings and kidnapped him and his wife, leaving Hershel and Theodore orphans. His obsession with the Azran civilization led him to climb the ranks of Targent. His obsession only grew after the death of his wife. Eventually, Bronev becomes the leader of Targent.
At some point in his life, he met Emmy Altava . He becomes the "uncle" of Emmy, and she starts to work for Targent.
He is later seen talking to Jean Descole and battling with him and Raymond at the the Nautilus Chamber of Akbadain. He tries to take off his mask while Targent guards are holding Descole on the ground. Raymond throws a smoke bomb and runs off with his master. He says to not worry about them and continues to order his men around.
Eventually, thanks to the assistance of Luke, Emmy, and Sycamore, Layton, alongside Luke, boarded Targent's airship. Confronting Bronev, the latter introduced himself to Layton, and was about to force Layton to leave, at gunpoint, when Aurora, feeling threatened, created a mental shockwave that caused the airship to malfunction. As it started to crash, Layton, Aurora, and Luke fled the airship, but not before Bronev glowered at Layton.
Later on, he became a secondary villain, as Professor Layton and co. battled his agents across the world, including the double agent Detective Inspector Leonard Bloom, who was unmasked by Layton as a spy. When Layton and co. attempted to solve the mysteries of the Azran civilization, Bronev sent his agents Bishop and Rook to prevent this from happening; however, thanks to the cunning of Layton, as well as the incompetence of Bishop and Rook, they failed in their mission.
When confronted by Layton and Desmond Sycamore, in The Nest, Bronev attempted to recruit Layton into Targent by threatening his parents, only for Sycamore to call Bronev's bluff. Bronev then left, leaving Layton and co. in his office; however, when Aurora suddenly regained her memory, she realized that she could have been used to reveal the legacy of the Azran civilization, something which would apparently unleash terrible consequences upon mankind. Aurora then threatened to commit suicide, only for Layton to convince her otherwise.
However, Sycamore used that moment to reveal his identity as Jean Descole, much to Layton's chagrin. As Layton and Descole pursued one another to Froenborg, Bronev remained a background villain, waiting to see who would get to Froenborg first; when Layton and Descole confronted one another, Bronev appeared, forcing Descole to throw to Bronev a keystone of tremendous importance - only for Layton, Luke, and Emmy to take it back.
However, the tables turned, as Emmy revealed herself to be Bronev's niece, and by extension, a Targent spy. She reluctantly forced Layton to hand the keystone over, allowing Bronev to advance into the Azran ruins, intent on ressurecting the Azran civilization. Such an action fostered a temporary yet unstable alliance between Descole and Layton (much to Luke's disgust), in order to stop the more important threat.
Further on, when Descole had been hit by an Azran trap, he revealed that he and Layton were brothers; when Layton and Descole were children, their parents, archeologists researching the Azran civilization, were upon the brink of a major breakthrough. However, Targent kidnapped the two, leaving Layton and Descole to fend for themselves; when the Layton family adopted Layton, he and Descole swapped names so that Layton would have a peaceful life, and so that Descole could plan his revenge against Targent. According to Descole, his birth name was Hershel, and Hershel (Descole) gave his name to Layton, who then became "Hershel".
As Bronev resurrected the Azran Legacy, vast amounts of highly-advanced golems emerged from the now-levitating ruins; after nearly destroying Froenborg, they threatened to continue across the world and destroy the entirety of human civilization. Aurora revealed that the golems had been created by the Azran millennia before, but they had rebelled, and were sealed away, with Aurora acting as their guard.
Bronev broke down, revealing his past: the death of his wife, whose last wish had been for him to use the Azran's power to create a peaceful, better world, caused him to accept Targent's mission, and become their leader.
As the ruins collapsed, following the efforts of Layton and co. to stop the Golems, Bronev saved Emmy from falling off the ruins. He was later arrested, alongside the remainder of Targent, by Inspector Grosky; as he did so, he apologized to Layton, calling him by his birth name, Theodore Bronev. Layton refused to answer by that name, saying he was called "Hershel Layton", and that Bronev had no right to call himself a father. However, Layton then said that he looked forward to Bronev becoming an archaeological friend of Layton's, regardless of their past.
His character profile in Miracle Mask is only unlocked after solving all 150 normal puzzles in the game.
In the final scene of the US version of the Miracle Mask, Bronev remarks "It is perfect weather for a day of world domination" when he first gets out of the car. This line is dropped in the British version.
This last point is heavily ironic, given the fact that Bronev joined Targent following the death of his partner, who wanted him to utilize the Azran Legacy in order to build a peaceful world. However, he is prepared to kill people if necessary - whether this is a bluff or not is unknown.
His English first name Leon may come from his lion-like appearance and his determined personality.
Strangely enough, his Japanese first name (Bronev) appears to be his English last name.
Bronev seems to be a tribute to Ernst Stavro Blofeld the primary villain of the James Bond film series. The similarities to the famous supervillain include the operation of a large, evil organization, a similar sounding name, and his initial appearance with a hidden face while stroking a cat (or a ferret in Bronev's case).