Master Wayne (Matthew Warner)

Matthew Warner is a derranged billionaire child who has convinced himself that he is Bruce Wayne. Using the alias of

Master Wayne, Matthew commits heinous crimes often in-order to feel closer to his namesake.

History
Matthew Warner was the wealthy son of billionaires Donald and Victoria Warner and grew up in a mansion with his butler, Mr. Taylor. Matthew grew up idolizing Bruce Wayne and eventually ordered the loyal Mr. Taylor to murder his own parents so that he could become more like them.

Together, Taylor and Matthew (who at this point only identified as "Master Wayne") framed Two-Face and Mr. Zsasz for his parents' deaths by making the crime-scene resemble the criminals' respective modus-operandis. The two proceeded to go on a serial-killing spree while using said modus-operandis to further shift the blame onto the super-villains. All the while, Batman believed Matthew to be an innocent and stayed in touch with him due to their percieved shared trauma.

Batman eventually caught on to their game however and managed to find and confront the young Matthew in the graveyard where the Warners were buried. Here Batman saw Matthew scratching out his parents' names on their epitaphs and scrawling in "Thomas and Martha Wayne". He had also carved, "Thomas" and, "Martha" into his own cheeks to further his descent into madness. Following the confrontation, Matthew was arrested and while only a child was sent to Arkham Asylum for treatment.