Book 5. The new Lords of Baator and Abyss.
.....
Six months have passed since the World Gate on the Sinux Magic Tower received hundreds of thousands of people in less than a day. Such a massive influx of life forms drew the attention of the powerhouses in the empire, mostly because more than ninety percent of them were aliens, foreigners from a different world.
At first, things were fairly calm since the ruler of the Sinux Magic Tower was a Law Engraving existence, and his authority in the empire was large enough to quiet all other Rank 5 life forms about things happening in his territory. Since the aliens were all Rank 0 life forms and Heinz communicated that the Daybreak Clan would handle them, no Rank 6 powerhouse bothered with them anymore.