WARNING: The following contains spoilers for Teen Titans Academy #5, on sale now from DC Comics.
The Bat-Pack is a group of young investigators at Teen Titans Academy, and their investigation of Red X came to an end when the mysterious student of the academy revealed his identity to them. However, the Bat-Pack's heroic origin story was traded as a toll for the Red X identity reveal in Teen Titans Academy #5 by Tim Sheridan, Rafa Sandoval, Jordi Tarragona, Max Raynor, Alejandro Sanchez, Alex Sinclair, and Rob Leigh. And the origin of the Pack revealed how Diego was transformed into a vampire hybrid by way of the same serum that transformed Kirk Langstrom into Man-Bat.
Diego was sent to the Beaumont School For Children in Bludhaven, which is where he met Lucas and Merissa. The three junior detectives ended up uncovering a plot between Beaumont's head administrator and Dr. Grusel that involved experimenting on the orphanage's children with an experimental serum. The Bat-Pack ended up helping Nightwing stop Dr. Grusel's version of Man-Bat, but not before he injected Diego with an advanced version of the serum that Kirk Langstrom used on himself.
While Diego was strapped to an examination table, Grusel discussed Kirk Langstrom's inability to see the full potential of the Man-Bat project. His latest serum, the one he injects into Diego, aims to end the human condition which he sees as a disease. Grusel despises Langstrom's Man-Bat because it ruined the legacy of his work, something he believes he can fix with Diego and the other Beaumont orphans.
Famously, Kirk's serum turned him into an unstable monster. Man-Bat #5 reveals just how separate Kirk really was from his Man-Bat persona as they battled for control of his mind and body. This new serum was designed to grow and adapt with the child, slowly reworking the subject's DNA with age. This made Diego's transformation much more stable and didn't dampen any of his natural personality traits when he transformed into a human/vampire hybrid. He then adopted the new identity of the Chupacabra and formed the Bat-Pack alongside Lucas and Merissa.
It's now up to Chupacabra to carry on Kirk Langstrom's legacy after his unfortunate end in a back-up in Detective Comics #1040, by Dan Watters, Max Raynor, Arif Prianto and Rob Leigh. While most of Man-Bat and Kirk Langstrom's legacy is filled with terror and destruction, he did the best he could to course-correct before his recent death. Langstrom was attempting to merge his human consciousness with the Man-Bat in order to become a more humanized version of the monster he became.
Chupacabra has a chance to uplift Man-Bat's legacy as he continues to solve cases with the Bat-Pack. Diego has already shown himself to be a selfless hero at a young age and his powers will continue to grow with time. Chupacabra has the potential to be the hero that Langstrom never could and become a powerful ally to Batman, the Teen Titans, and maybe even Red X in the future.