There is a bit more to this event, but Father is not sharing that information right now. The attack on the Composer was designed to cause damage to the lower planes and the Composer. Because the Composer spent so much time with the Reapers, and taught them a lot about the planes and themself, it gave them the knowledge the needed to actually cause significant damage.If the attack had succeeded, and they had defeated the Composer, one of them would have become the Composer and still would have had to clean up their own mess. But at least it would have been a functioning Composer to handle it.But instead, they didn’t, so the region was felt was a partially functioning Composer, unable to help out or transfer their power over to someone who could. Luckily all Reapers had the same training, so they were able to fix things eventually, but not without losses.Now that knowledge about the planes and the Composer’s abilities is not openly shared, so if something similar were to happen to a Composer again, the same damage won’t - shouldn’t - be possible.And one more fun fact about the story - Father was there…as a Reaper. Perhaps Joshua will get to learn that, and more details about those events.