How did the qhal acquire the ability to travel in time

The qhal have been able to travel through time for over 500 years. They are able to slip from on future age to another. This means that they have lost such things as memory and death. Agent Harrh is a time-mender. He is one of the few who can go back in time. He makes small adjustments to reality. However, even he cannot escape the dangers of time travel.

The qhal were able to time travelling when they found the first Gate in a dead world in their own sun.

Explanation:

Who made it, or what befell those makers, the qhal of that age never learned. Their interest was in the dazzling prospect it offered them, a means to limitless power and freedom, a means to shortcut space and leap from world to world and star to star - an instantaneous travel.