I was more referring to some of the things Gil himself said about seeking Enkidu's reincarnation.
If I had to guess, since Gil knew an almost disturbing amount about everything, he knows that souls are ground up, so there must be a reason he thought Enkidu would have one, and I'm relatively sure there is at least one NP for reincarnation, since it's such a big part of some large religions, so there must be mythic artifacts pertaining to it, which would mean even odds Gil has one, and if he did, he would have used it on Enkidu after he died.
Most likely on himself as well in this story.
Some NP soul fuckery is the only way I can think of for him to have incarnated as a prince of the kingdom.
That or the Grail being a dick, but the Grail has proven in canon to be unable to do much of shit to Gil.
Word of Nasu: Nothing Controls Gilgamesh.