Thinking back to this and the question of Amdapor having Sin Eaters, I reckon it may not be entirely farfetched that the First has been slowly flooding for eras now. It might also explain why it's taking the Derplander all his strength to defeat the Kuribu in the trailer, the one summoned into Amdapori times was far weaker as the Flood of Light in the First was less widespread, but now it covers most of the first and as such Kuribu are much more powerful. It may also explain the power differential between the Amdapori Lion and the Holy Cow, the Holy Cow was (likely inadvertently) summoned into Eureka much more recently and as such it kind is much stronger than it was in the days of Amdapor.