"W-WE DIDN'T KILL ANYTHING?!"
The Elves all had shocked expressions on their faces, and understandably so. They had just been told by Rey that they never killed the Boss Monster.
They also never killed any of the other Monsters on their way out.
'Why would I let them take such precious EXP away from me? I killed the Boss and the other Monsters to further test out my [Perfect Divine Growth] and managed to Level Up and get more Skills.'
Unfortunately, the Monsters in the Dungeon were not as diverse as the ones he encountered in the Royal Dungeon.
Perhaps it was due to lack of conquest on the part of the Elves, which led to stunted Evolution, or the abundance of resources for the Monsters, or several other factors that Rey couldn't possibly know, but the Monsters in the Dungeon were very similar to each other and had similar Skills.
Of course, that didn't mean all of them were the same.