Layered Hand
Earth's Fold of Reality slowly solidified. In this state of flux, it became comparatively easy to cross over. This was especially the case since the Milky Way was a predominantly Fifth Dimensional galaxy. Since Earth was also currently entering the Fifth Dimension, it was more a process of assimilation than evolution, helping to facilitate the crossing over all the more.
There were quite a number of powers waiting for an opportune time to cross over and many that had already done so. Having lost the protection that came with being a lower Dimensional world, Earth had begun vulnerable and thus had no choice but to gain the strength to defend itself.
This moment was one that many had been preparing for a long while. Those that came from higher order worlds had many special techniques for predicting and marking the borders of evolving Folds of Reality and had thus scouted out the region long in advance.