Much like the other Watchers of Azeroth, Algalon had his own purpose. However, his particular purpose was on a much larger, universal scale. By his own words, Algalon has been to countless worlds and performed the same task repeatedly: Analyze the world the Titans created, and detect any “systemic corruption” — anything that would keep that world from thriving as the Titans had planned. Once it was determined that the world was indeed corrupt, Algalon would send one of two signals to the Titans: Reply code Alpha, signaling that the world was in fact, just fine, or Reply code Omega, signaling that corruption had been detected and the world would be re-originated.
The Titans didn’t bother returning to the world in question; instead, a signal would be sent to a re-origination device that would proceed to melt the world into its core elements and rebuild it according to its Titanic blueprint. There was nothing horrific in this process, as far as Algalon was concerned; he was merely doing his job. Think of Algalon as an exterminator. He shows up to check and see if your house is full of termite, only rather than simply tenting the house, Algalon would break the whole thing down and rebuild it, termite-free.
Unlike an exterminator, however, Algalon has little caring or empathy for the mortals of the worlds he observes. To him, they are inconsequential. Highly logical and systematic in his observations, Algalon is almost like a machine. He was built with one purpose in mind, and he goes about and fills that purpose without question, because that is what he was programmed to do.
Until, that is, he encountered Azeroth.
The mortals of Azeroth had done the unthinkable; they’d showed a stoic Watcher that there was more, far more to the universe than simple order and re-origination. And Algalon was left perplexed and almost angry at this realization, not because the mortals of Azeroth had done anything wrong but because he had suddenly been granted the knowledge that these tiny, inconsequential mortal lives that he had been eradicating for countless years were all quite possibly creatures of free will, creatures that did not want to die. Creatures that perhaps did not deserve to die.
In this realization, Algalon altered the Reply code to Alpha and ordered the mortals who so brazenly interrupted his scanning to take it to a place of power, close to the skies. Once the Reply code was taken to Dalaran, the altered code reset the designation of the world, and it was safe from re-origination … for now. As for Algalon, he was left with his task incomplete for the first time in his existence. Algalon was an observer, Algalon was assigned to scan the world for any outlying corruption leaching into the order of the world.
With Azeroth, he was presented with a world that was admittedly corrupt — but in that corruption was perhaps the saving grace of the world itself. This concept was so strange, so foreign that Algalon could not simply let the world be undone. This deviation from the Titans’ programming was so unique and bizarre that it deserved further observation.