The Elite Guard were Cadden Blackthorne's personal guard unit. Though by no means bodyguards, the Elite Guard had much more akin to a SpecOps unit than anything else. As their name implied, the individuals underwent rigorous training and were willing to fight to the death if necessary.
The Elite Guard were, in fact, officially disbanded after the Xen'Chi's attack on Mandalore. Half of the members were killed in active combat, while the other half went their separate ways after Cadden's disappearance shortly before the Battle of Bandomeer. They maintained contact, but for safety and security purposes made it a point to not establish physical contact until Blackthorne was found.