Their advancement to become the god of the pathway of slavery is their fastest advancement ever. They literally progressed from initial control of the pathway to a 100% fusion rate and successful advancement all in one day.
No other pathway was so fast. But they can't say that the advancement to become the god of slavery was fast because it was easy. If it were easy, they wouldn't be the first god of slavery despite the numerous attempts by many predecessors before them.
In fact, the advancement was not easy for them. Just the fact that they didn't initiate the fusion and the subsequent advancement shows just how out of their hands everything was.
The Worm of Subjugation wanted to make them become the god of slavery by force. As soon as they tried to gain control of it, they either had to become the god of the pathway or be enslaved and devoured by the Worm of Subjugation.
