The following contains spoilers for Sword of Azrael #1, on sale now.
Despite existing since 1992 when first introduced in the miniseries Batman: Sword of Azrael, much of the lore of the Order of St Dumas has been left largely unexplored, despite being so deeply connected to the origin of the vigilante Azrael. This allowed them to remain a constant enigma throughout their various appearances within DC Comics. The amount of power the secret order wielded, and their origins were only partially revealed through storylines like Batman & Robin Eternal, Detective Comics: Deus Ex Machina, and the two solo comic series for the two Azraels'; Jean-Paul Valley and Michael Lane.
The revelation in the recently released Sword of Azrael #1 (by Dan Watters, Nikola Čižmešija, Marissa Louise, and Hassan Otsmane-Elhaou) that the ancient Knights Templar who spawned the Order of St Dumas still exists within the DC Universe completely changes what comic book fans knew about Azrael and the Order of St Dumas. This new Knights Templar organization could indicate that there are other secret sects similar to the Order of St Dumas and that Azrael may not be the only kind of Avenging Angel.
The basic origin provided for the Order of St Dumas in their first appearance in Batman: Sword of Azrael (by Dennis O'Neil, Joe Quesada, Kevin Nowlan, Lovern Kindzierski, and Ken Bruzenak) was that the Order was originally a part of the Knights Templar during the historical Jerusalem Crusades. However, they broke off from the Templars after their patron saint defied the organization and went rogue. The Order of St Dumas then took over the legacy of the Templars, creating the Azrael assassins to bring divine justice to those who threaten the order as it runs various government organizations from the shadows.
This was until the Azrael known as Jean-Paul destroyed the organization in the 1996 comic book storyline Azrael: Angel at War - The Fall of St Dumas (by Dennis O'Neil, Barry Kitson, James Pascoe, and Demetrius Bassoukos). However, during Sword of Azrael #1, Jean-Paul Valley discovered the young French woman; Brielle Arnier during his seclusion in an island monastery. He learned of a previously unknown organization that bears the symbol of the Templar Knights that were attempting to capture the woman.
While the vigilante first assumed that this group was a remnant of the Order of St Dumas, the former assassin learns that this group is the original Knights Templar organization that the Order of St Dumas defected from during the Crusades. Jean-Paul also discovers that the reason these Templars are trying to acquire Brielle Arnier was that she had been given similar psychological training to that of the Azrael assassins. She was an assassin dedicated to another religious order under a different angel-originated moniker.
The introduction of a new Angel of Vengeance that has taken up the moniker of the archangel 'Sariel' has brought a massive revelation that there are other Templar-themed assassins connected to the Order of St Dumas other than Azrael assassins such as Jean-Paul Valley or Michael Lane. This opens the possibility that there are perhaps several secret societies derived from the Knights Templar that function similar to the Order of St Dumas. They may each have their own form of assassin or enforcer that bears the name of biblical archangels.
The notion that there were other organizations similar to the Order of St Dumas was first introduced in the 'Dark Knight of the Soul' storyline from Batman: Urban Legends #8-10 (by Dan Watters, Nikola Čižmešija, Ivan Plascencia, and VC's Ariana Maher). There Azrael met a religious zealot by the name of Poor Fellow who claimed to serve another group that had broken off from the Templar Knights. But with the revelation that the original Knights Templar organization is still active after centuries of assumed disbandment, the Order of St Dumas may not be as powerful as once assumed. It may have been but one sect of a much larger religious organization that is only now being revealed to the DC Universe.
This has made the Azrael mythos far larger than any fan of the crimson-garbed vigilante could have predicted from the six-part limited series. This may lead to further plans for Azrael as a more important character in the broader DC Comic universe in the wake of the Dark Crisis event. As has been represented by Azrael and his recently introduced villain; Poor Fellow making an appearance in DC vs Vampires: All-Out War #1, with Azrael set to play a reasonably large role in the comic series.
Regardless, it is evident that the pantheon of DC Comic secret societies is going to be completely shaken during the remaining five issues of Sword of Azrael. Comic readers have much more to learn about the resurgent Templar Knights as well as other Templar-based organizations that may be conceived in the coming issues.