Fifteen years ago four members of the Flag Five were killed by The Terror's henchmen in front of Arthur Everest at a young age after their ship crashed on his father and the supervillain had used weaponized syphilis to destroy their eyes effectively rendering them blind. The Terror stopped short of killing all of them and ordered his henchmen to crush the hands of sole attack survivor Straight Shooter. Christian Soldier's pet and the team's mascot Onward (who would rename himself Midnight) had a turbulent relationship with Straight Shooter both would reflect on years later, though the canine companion suffered from heartworms and related diseases for a while and happened to be at the local veterinarian at the time of his comrades' ends.
Before this Miss Lint manipulated Straight Shooter (really Uncle Samson's sidekick and future vigilante Overkill) into giving her the necessary access codes to breach the Flag Five's HQ and presumably put The Terror's plan into motion, though not before metaphorically dumping him and breaking his heart.
However, their deaths and losses would be avenged by fellow superhero Superian when he seemingly killed The Terror a year later and again when he finally helped subdue the villainous madman once and for all on the latest memorial of the Flag Five's last stand and demise.