Child-Gil

Child-Gil (子ギル) is the youthful form of Gilgamesh takes upon drinking the potion of youth from the Gate of Babylon.

Background
Gilgamesh as a child was considered to be a king with aptitude for ruling superior to all others, the "epitome of the ideal boy king." Although Enkidu was created to reprimand Gilgamesh while he was still a child, Enkidu was not allowed to combat Gilgamesh until they could fight as equals. As Enkidu watched the young king, he could not understand what flaw he could possess that would require correction, but he witnessed the change firsthand as Gilgamesh grew. Changing into a despot who caused the masses to lament, Enkidu was presented with a reason to confront him.

Appearance
Child-Gil possesses the same blood-red eyes and golden hair that makes him older-self stand out from others. Shirou is unable to identify him from sight at first in comparison to his older self, and he finds it hard to believe they are the same person even after being told.

Personality
In contrast to his older self, Child-Gil was praised and lauded by the citizens of Uruk to the point of infatuation as tolerant, sage, fair, and moral. The only "flaw" that could be described at the point is that he respected the gods without submitting to them.

Gilgamesh declares his Child-Gil and his adult self to be fundamentally different, much to the point where he speaks of his childhood self in a secondhand manner. His adult self cannot perceive the memories of his younger self despite an otherwise flawless memory, and he believes Child-Gil to be the same in nature. Gilgamesh says Child-Gil very well may have stopped his growth had he known how his adulthood-self would act.

Fate/stay night
Child-Gil does not appear in Fate/stay night, but it is mentioned that during the intervening years between the Fourth Holy Grail War and the Fifth Holy Grail War that Gilgamesh took the potion of youth to allow him to live in modern society without causing a problem.

Abilities
Child-Gil is weaker in ability than his older self, lacking sufficient magical energy to summon a large amount of Noble Phantasms from the Gate of Babylon. Despite that, he lacks the "Conceitful skill" possessed by his older self and displays better usage with his limited weaponry, so it could be said he is stronger is a child in that sense.