He searched for suitable worlds, connected them so the divine kingdom could draw energy, remodeled the Tower of Babel during breaks, or passed the time by constructing buildings on the largest Floating Mountain outside.
Time continued to pass. At first, Yinsen had wanted to finish the divine kingdom's construction in one go, refusing to leave until it was done.
Later, he discovered that the work was troublesome and extremely time-consuming. Gradually, he stopped fixating on it. Every now and then, he would head to the Venus to relax for a few days, or visit familiar worlds, go on dates and get affectionate with Diana, Ada, and Selene, and continue deepening his relationships with Yoruichi and Bulma.
Meanwhile, after Illya, Rin Tohsaka, Leah, and the others finally graduated from Hogwarts, Yinsen, as their teacher, once again began personally teaching Leah all kinds of knowledge, including practical combat training—except her opponent was not Yinsen himself, but illusions he had created based on certain people he knew.
They were called illusions, but they possessed attacking power as well. Anyone who relaxed their guard because they thought such attacks could not hurt them would suffer for it. Illya had learned that lesson the hard way.
Besides training, Leah also began regularly returning to the Diablo World where she had been born to adventure. She could enter and leave that world as she pleased without being discovered by Heaven's angels because, after so many years of study and enhancement through specialized potions, all the demonic god power within her had become nourishment and transformed into an energy nature Leah preferred to use.
The characteristics displayed by this energy were similar to Holy Light, though it differed quite a bit from Azeroth's Holy Light. Instead, it was somewhat closer to the Holy Light Yinsen had mastered.