Initially, it felt very easy as if this wasn't even a challenge to them. The first steps were easy and light, as if they were walking on air.
They felt a surge of energy and joy, as if they were being lifted by the angels. They smiled and increased their speed even more.
But as they climbed higher, they started noticing a change. The steps became harder and heavier. They felt a pressure on their legs and feet, as if they were carrying a heavy weight on their back. Many started to sweat and pant, feeling a strain on their muscles and lungs. They slowed down and paused, feeling fatigue and pain.
If they could use magic, they could try strengthening their bodies. However, even that wasn't allowed.