The Dalish believe there are strong forces surrounding the great natural monuments of Eden, and they believe meditation at these sites grant them great knowledge and understanding of the world around them. It's no coincidence that these spots are the earthly manifestations of the leylines effects on Edens surface, which is why such great power can be drawn from these monuments. The increased mana flow from those who sit and meditate increases the brain function and therefore allows more abstract thoughts bloom in those who may have not had the inspiration before. This sudden burst of inspiration and understanding is part of why these spots are holy and greatly spiritual to those who don't understand the power of the leylines. Towns are erected around these spots and they become cultural markers of the Dalish, where the great art of the civilization is spawned.
Harken wishes for the Leylines to be restored to their former strength and reach. Neil Endari has been tasked by Harken to find a way to rebuild the leylines and harness their power to save Eden from the Withering. As the leylines are invisible to most, Harken has endowed a blind man with the power to seek out these leylines. That man is Apollo of the Soul, and it is his job to lead Turning Catalyst Endari to restore the worlds leylines so that the Gods and the mortals alike may stand together to prevent The Withering.