Enter Cloud Chaser the Clavicle Breaker and Starry Eyes the Menacing, once normal weather ponies until they were approached by Princess Twilight Sparkle to try out to be one of the guards of harmony on Rainbow Dash’s recommendation.
Twilight, remembering Cloud Chaser’s help during the breezie situation and Starry Eyes’ courage during his time in the Wonderbolt Reserves, thought that they would be just the gentle hooves that Fluttershy would need as well as being acceptable protectors. However, during tryouts, the duo turned out to be much more deadly than Twilight had anticipated. They obliterated the competition and injured most of the other ponies.
No pony talks about what Discord did during his tryout. The screams…
Interestingly, they were like puppies towards Fluttershy but they would fight ruthlessly to defend her. Thus they were dubbed the “Watchdogs of Kindness”.