descend

An action descends when you move downward or downwards, like a rock rolling down a hill.

Imagine you're hiking in the mountains and you're climbing up towards the summit. As you reach the top, you can start to descend by walking downhill back to your campsite. Descending is often used to describe movement from high to low, whether it's physically on a mountain or figuratively, like when you have to deal with a difficult situation and things get worse before they get better. For example, "The company descended into chaos after the scandal broke" means that things were going well for the company, but then got much worse very quickly.