My take on The Music Meister (Darius Chapel): Darius Chapel was born to a musical virtuoso named Caden Chapel. His mother was named Allegra, but she died giving birth to Darius. A beautiful composer of orchestral music, Caden hated modern music. The modern vocalizations took away from the sophistication of classical music, in his eyes. So as he raised his son, Caden tried to force his son to conform to his interests. It never quite worked, since Darius was fascinated by the world of the theatre. He so dearly wanted to sing on stage, either solo or as part of a choir.
So when he once naively told his father that he wanted to be a singer, it angered Caden. No member of the Chapel family would be a singer under Caden's roof! So for years, Darius had to repress his musical urges. He had to hide his true nature from his father. It was a repressive household, one where the only music allowed was that of orchestra pit music. Instrumentals. No vocalizations whatsoever. It was stifling. A perfect metaphor for the mentally abusive household.
When Darius went into middle school, he secretly started performing for the school choir. He hid this info from his father, and got away with it for almost a full year. But near the end of the year (as Darius was just turning 12 or 13), bullies began to pick on him. He tried to ignore them at first, but eventually they got physical. When he accidentally let out a scream as they went to hit him, they unexpectedly stopped in their tracks. And that's when Darius discovered his gift.
Somehow, he was born a mutant. He hadn't realized it until now, but his voice has the power to entrance all who hear it. Depending on the pitch and the modulation, he can make people behave differently and do different things. For a timid 13 year old boy who was bullied all his life for being a singer, this knowledge was salvation. A manna from heaven. Using his gift, he protected himself from harm. When he sang, he could hypnotically trick his bullies into making fools of themselves. At home, he used his voice to make his father stop repressing him. Their home became dictated by Darius's rules. For the first time in his 13 years, he had control of his fate.
The ability to control others with his voice slowly went to his head over the years. He still wanted to be a singer, of course. But as he moved from elementary school into high school (and then high school into college), he began to feel like it wasn't enough. No, merely being a singer didn't present enough joy to him. With his voice and his ideals, he could change this world! There'd be peace on earth, if everyone would just accept him as their all knowing dictator! Fame, adulation, riches, all will be his!
These thoughts led him to become The Music Meister, the villainous virtuoso of crime! On his first big crime spree, he successfully enslaved almost the entire world. As seen in Batman: The Brave and The Bold, he successfully hypnotised everyone on earth besides Batman. He was this close to being the emperor of earth! This close! He was almost the idol of all! But no! That damned batman stopped him, and he was locked in a soundproof cell in arkham for years. For years upon end, he stewed in prison, angrily plotting his return to villainy.
Finally, he was freed from arkham on good behaviour. He was finally going to become a big name in crime again; he'd finally see his goals realized! He would rule this world! But sadly, nobody seemed swayed by his voice anymore. Well, I mean…technically people still obeyed his voice. He was able to commit a series of successful crimes. But because of The Mad Hatter (who'd also broken out of arkham), Darius receives no credit for his musical crimes. He's ignored, and being ignored is the one thing a man like him can't stand. He's a showman! He lives for fame and glory! You can't neglect him! He deserves to be worshipped and idolized!
Darius kept commiting crimes, but every single time he did, people blamed The Mad Hatter. Apparently he was too minor for any detectives to think of him! Even that stupid batman doesn't seem to think of him! It sends his blood boiling. Realizing that nobody's ever going to give him the respect he deserves, he heads to a seedy downtown bar to drown his sorrows. It's there he runs who The Bookworm and Ragdoll, two crooks who've been having similar difficulties to him. All lonely and angry, the three of them agree to an informal alliance. And well… I think the rest was probably covered in my posts on Ragdoll and The Bookworm.