All the core positions in the Great Graveyard are tightly held; only when someone leaves does a vacancy appear. As an outsider, even with his outstanding contributions, he is still excluded.
Even if he made one of the grand dukes his mistress, it still wasn't enough to let him cross that threshold, because no undead wishes to add another member to divide their authority further.
As for waiting for those grand figures to relinquish their positions, he shouldn't even dream of it. How could a living person outlast the undead? Although they are not truly immortal, surviving a thousand or eight hundred years would be easy for them.
Thus, faced with challenges he couldn't resolve independently, Wayne, without troubling himself for too long, went directly to Holy Dragon Noah. Since they wanted him to continue infiltrating and even to advance, they had to help him deal with troubles outside.
"What kind of assistance do you want from me?"
