<p>Initially, it's stated that servants are kept in the world by the Holy Grail. (This comes up in the Good End of "Unlimited Blade Works," but I imagine this piece of information might have appeared earlier.) They also need a mana supply; note also that servants who had become separated from their masters in <em>Fate/stay night</em> did not immediately disappear. In the case of Gilgamesh, both of these conditions were fulfilled. The Holy Grail was still around, and Kotomine kept the orphans from the fire under the church and used them as a mana source.</p>

<p>In the events of <em>Fate/stay night</em>, other servants were also retained, even when the Grail was destroyed. In the "Good End" of the "Unlimited Blade Works" route, Saber stays in the human world. Rin has been supplying mana to her, and she asks Shirou to help her. Similarly, in the "True End" of "Heaven's Feel", Rider stays with Sakura even after the destruction of the Grail; per <a href="http://typemoon.wikia.com/wiki/Sakura_Matou#Heaven.27s_Feel" rel="noreferrer">the wiki</a>, this is possible because Sakura has enough mana reserves because of her connection to Akasha.</p>

<p><a href="http://typemoon.wikia.com/wiki/Gilgamesh" rel="noreferrer">The Wikia</a> also gives an explanation of what happened to Gilgamesh at the end of <em>Fate/zero</em>. (I cannot provide much more commentary on this, since I haven't followed the series lately.)</p>

<blockquote>
  <p>Due to his proximity, Gilgamesh is caught off guard and becomes drenched by the pollution that spills from the Holy Grail. He obtains a physical body, and because he has been incarnated into the world, he decides that it is time to once again unite the world under his rule. He continues to follow Kotomine after the war is over, and Kotomine provides him with energy drained from children orphaned by the fire to sustain himself. He decides to wait for the next Holy Grail War to cleanse humanity, so he retrieves a potion of temporary youth from his vault that reduces his physical age and allows him to smoothly blend in with society for ten years.</p>
</blockquote>

CC BY-SA 3.0
2017-04-02T05:29:13.073Z
If I've gotten something wrong or I'm missing something, please comment, and I'll either edit or delete my answer.
Maroon
CC BY-SA 3.0
2017-04-03T13:18:53.090Z
Seems good to me.  The last part is fairly important.  The possession of a physical body substantially lowers his energy requirement, as he no longer needs energy just to exist.  The youthful form further reduced his energy needs.

The servants are likened to extremely powerful familiars in the game, requiring magical energy well in excess of all but the greatest mages.  Rin's two endings point this out: without Saber she joins the Clock Tower; with her she doesn't because she is (1) way too big a target with such an awesome familiar and (2) unable to use much magic because it goes to Saber.
zibadawa timmy
CC BY-SA 3.0
2017-04-02T05:27:00.157Z
2017-04-02T05:27:00.157Z
Maroon
<p>I actually didn't understand why did Gilgamesh remain in the human world. What I understand is that he touched the Grail that's why he remains.</p>

CC BY-SA 3.0
2017-03-31T14:19:00.477Z
Because he's a king of kings you FILTHY MONGREL :D
Callat
CC BY-SA 3.0
2017-04-01T22:56:45.950Z
I believe he stuck around just because he was never killed and Kirei kept supplying him with mana so they could do a scheme together in the next Grail War. I'm sure one of our many Fate series experts will be along soon to explain all the convoluted intricacies of the situation, though.
Torisuda
CC BY-SA 3.0
2017-04-01T23:21:48.943Z
SHort version, he wanted another shot at the Grail, and there was no guarantee he'd be summoned again for the FIfth War.  The fake priest was down with it, so they tried.
Xavon_Wrentaile
<fate-stay-night><fate-zero>
Why did Gilgamesh remain in the human world?
# Why did Gilgamesh remain in the human world?
Posted by: username_0 on 2017-03-31
I actually didn't understand why did Gilgamesh remain in the human world. What I understand is that he touched the Grail that's why he remains.
**Tags:** fate-stay-night fate-zero
> **Comments:**
> **username_1**: Because he's a king of kings you FILTHY MONGREL :D  
> **username_2**: I believe he stuck around just because he was never killed and Kirei kept supplying him with mana so they could do a scheme together in the next Grail War. I'm sure one of our many Fate series experts will be along soon to explain all the convoluted intricacies of the situation, though.  
> **username_3**: SHort version, he wanted another shot at the Grail, and there was no guarantee he'd be summoned again for the FIfth War.  The fake priest was down with it, so they tried.  
---
## 1 answers
### Answer by username_4 on 2017-04-02. Score: 4
Initially, it's stated that servants are kept in the world by the Holy Grail. (This comes up in the Good End of "Unlimited Blade Works," but I imagine this piece of information might have appeared earlier.) They also need a mana supply; note also that servants who had become separated from their masters in *Fate/stay night* did not immediately disappear. In the case of Gilgamesh, both of these conditions were fulfilled. The Holy Grail was still around, and Kotomine kept the orphans from the fire under the church and used them as a mana source.

In the events of *Fate/stay night*, other servants were also retained, even when the Grail was destroyed. In the "Good End" of the "Unlimited Blade Works" route, Saber stays in the human world. Rin has been supplying mana to her, and she asks Shirou to help her. Similarly, in the "True End" of "Heaven's Feel", Rider stays with Sakura even after the destruction of the Grail; per [the wiki](http://typemoon.wikia.com/wiki/Sakura_Matou#Heaven.27s_Feel), this is possible because Sakura has enough mana reserves because of her connection to Akasha.

[The Wikia](http://typemoon.wikia.com/wiki/Gilgamesh) also gives an explanation of what happened to Gilgamesh at the end of *Fate/zero*. (I cannot provide much more commentary on this, since I haven't followed the series lately.)

> Due to his proximity, Gilgamesh is caught off guard and becomes drenched by the pollution that spills from the Holy Grail. He obtains a physical body, and because he has been incarnated into the world, he decides that it is time to once again unite the world under his rule. He continues to follow Kotomine after the war is over, and Kotomine provides him with energy drained from children orphaned by the fire to sustain himself. He decides to wait for the next Holy Grail War to cleanse humanity, so he retrieves a potion of temporary youth from his vault that reduces his physical age and allows him to smoothly blend in with society for ten years.
> **Comments:**
> **username_4** (2017-04-02): If I've gotten something wrong or I'm missing something, please comment, and I'll either edit or delete my answer.  
> **username_5** (2017-04-03): Seems good to me.  The last part is fairly important.  The possession of a physical body substantially lowers his energy requirement, as he no longer needs energy just to exist.  The youthful form further reduced his energy needs.

The servants are likened to extremely powerful familiars in the game, requiring magical energy well in excess of all but the greatest mages.  Rin's two endings point this out: without Saber she joins the Clock Tower; with her she doesn't because she is (1) way too big a target with such an awesome familiar and (2) unable to use much magic because it goes to Saber.  
---
