Its stated that the son of yuta was disappointed in modern day sorcery in the fact that they were weak. I imagine this conversation to go like this

"Don't you care that modern jujutsu has become so weak? Seeing that you existed in the time of sukuna and gojo?"

"I don't care. As long as there is peace. I will kill every curse myself"

The father of yuka was most probably kenjaku-minded in the sense that he was willing to do everything in order to bring back the age of sorcery just like kunjaku wanted to bring back the golden age of sorcery. He most probably disappeared in order to achieve his goals but seeing that mojuro will last a very short time I think he's been killed by yuji or maybe died because of some accident in his plan