It should be obvious enough that nothing like 'Eternal Skills' or 'Eternal Items' existed in the real world or in any realistic sense of the word. It was something conjured up by the World Will to mimic the digital world Draco and Eva hailed from, so while monsters may drop both skills and items, they couldn't be taken out nor were they 'real'.
They could only be used while in the fragmented Eternal Plane here, and only for the duration of their trial. Then again, Draco and Eva were already satisfied with the opportunity given and didn't dare to be greedy for more.
It was clear to them that they were dealing with the big leagues, and while temporary, they could finally get a glimpse of the 'endgame' of the universe and where the limit lay.
Whatever the case, Draco and Eva put the speculations aside for later. They decisively scanned the area around them with their Control and didn't sense any enemy presence, so they began moving forward.