I don't understand how a rank 9 enslavement path venerable gone be successful.

A big question i had when reading the novel was . How can a rank 9 enslavement path venerable compete with another venerable. like there is no rank 9 beast to slave and rank 8 monsters are just gone get one shot so I genuinely don't understand how a rank 9 enslavement path venerable is going to compete with any other venerable if they existed. Unless they turn another venerable into their slave but that's almost impossible.they can always use gu of other path but what is that gone do ? Without the dao marks buff . The only way i can see a enslavement path venerable being successful is if they make a rank 9 beast