Warning, this article contains spoilers for Robin King #1.
Robin King is DC's most sadistic version of Batman yet. Dark Nights: Metal has produced the most frightening versions of Batman to date after the Batman Who Laughs recruited the evilest versions of the Caped Crusader from across the multiverse to conquer the forces of good. But none rival the Robin King in terms of villainy. Robin King's origin story separates him from every other evil version of DCs heroes introduced in Dark Nights: Metal, because the tragedy that turned him evil is the same that made the real Batman a hero.
Robin King is The Batman Who Laughs' lieutenant. His story begins with the death of his parents. Like Batman of Earth-Prime, Robin King's parents were gunned down in an alley. However, the big difference between the two versions of Bruce Wayne is Robin King was the one who murdered his own parents. He has been evil since adolescence and killing his own parents was just the catalyst that caused him to become a villain. He's now obsessed with freeing other children from the constraints of rules and morality.
After attending his parents' funeral, the young Bruce Wayne decided he would become a Robin, a symbol of freedom for the youth. He used the Wayne fortune to arm himself with some of the most exotic weapons and resources known to man. He then began taking heroes down quickly and methodically. In Robin King #1 by Tony Patrick, Peter J. Tomasi, Daniel Sampere, and Riley Rossmo, this twisted version of Bruce Wayne wages war on his Earth's heroes. His version of the Bat-signal, gifted to the Gotham City Police Department, had a hidden microwave cannon that gruesomely burnt Jim Gordon's face.
He would also attach a black hole inversion ball to Firestorm's head, causing him to dematerialize. Robin King skewers both Hawkman and Hawkgirl using a strategically placed lightning rod. After he's done decimating many heroes on his own Earth, Robin King is approached by The Batman Who Laughs, and, like many other alternate versions of Bruce Wayne, is recruited into his army. The Batman Who Laughs tells the Robin King he will undoubtedly become one of the greatest "Dark Knights" ever.
Robin King is the most twisted version of Batman because the great tragedy that inspired his transition was the same tragedy that caused Bruce Wayne of Earth-Prime to become the Dark Knight. He is Bruce's potential for evil materialized. Robin King is a younger, more ruthless version of Batman that has been evil for most of his life. His cruelty makes him truly worthy of the title "King of Pain," bestowed upon him by The Darkest Knight.