#Both Sonic and Gilgamesh are misunderstood characters. I understand because they're hard to understand.

[sakuraswordly]

You want to know why King Gilgamesh chose to go back to Uruk and was very serious about becoming a king who ruled his people after the quest for immortality? [Connect to this hint]

Sonic Prime is the best example, Shadow tried to reason with Sonic and leave those friends behind because they were not real friends they knew. But why did Sonic give his life to his friends whom he met only briefly, even Nine?

Shadow: It's the end of the universe and you're still thinking about your friends! Sonic: Of course, I am! They're all here, fighting, sacrificing themself for me!

In the same way the people of Uruk, they're like Sonic's friends who suffer because of King Gilgamesh's actions. After Sonic knew it was his responsibility to destroy the world, the same way after King Gilgamesh realizes it was his fault for Enkidu's death and his people's suffering. Both Sonic and King Gilgamesh choose the right thing and never leave them behind, not because of their duty but because they're like their family to them. Even though they had never spent much time with these friends before.

Gilgamesh:  I had no reason to fear death. I could simply be there, in that era, presently invincible, and gaze upon the distant future with no need for the passage of time. — mankind’s oldest story. My duty as hero who would be spoken of in ages to come would be fulfilled. That’s all there is to the story. I was born as a human being, and after tasting joy, as a human being I died. I’m sorry. Earlier I said that I have been perfect since my birth, which was inaccurate.

he is king. he is god. he is neither, in the end. perhaps it is lonely.

(Note: "Mankind’s oldest story I was born as a human being." In Tsubasa of Phantasia, Gilgamesh grow to feel more human and gain more human emotions that's why he said that he's Mankind’s oldest story. Gilgamesh travelled and came back as "a normal human.")

Both Sonic and Gilgamesh never be a hero but because of their friends, they call Sonic and Gilgamesh as "Hero". You can see how much the people of Uruk care for King Gilgamesh just like Sonic's friends care for Sonic. This is the same reason why Punch Whalen chose to go back to her friends and never leave them behind, no matter how bad the action or betrayal of her friends. (And this is why Asha chose Punch and be by her side as her friend.)

[sakuraswordly]

Let me continue from gilgil-machine

You understand now why Sonic said, "I don't mind playing villain role for a while". (Note: Villain role means the king role for King Gilgamesh)The same way for both Punch and Gilgamesh, if they did is the right thing, they are really glad to sacrifice themself for the people they want to protect even if they will end up becoming an arrogant asshole, misogynist, sadist and villain.

[Note: Sonic's different from Shadow.

If the world chooses to become my enemy, I will fight them like I always have.

Shadow's decision never changes no matter what happens but Sonic's decision can be changed every time that's why you can't tell that Sonic can kill Dr Eggman anytime .As for Shadow, he still observes that Dr Eggman should be killed or in jail if without a reason. Shadow's personality can be changed if he breaks(You can see when Shadow with Maria) but Sonic never change no matter how broken Sonic is.]

And this is why Sonic trusts Punch and forgives King Gilgamesh too in Tsubasa of Phantasia, even Sonic accept them for how they will be.

Punch: Sonic...I choose....to side with darkness and take my revenge path.  Sonic:.........I see.... Punch: This doesn't surprise you, Sonic? Sonic: Not at all. I knew that was the only choice you could make. Punch: So you see Sonic. I am not a kind person from the beginning...................I will stand over you all. That’s why I live, to slay everyone who stand in my way...So now....Sonic...you're standing in my way! Sonic: I know. I'm ready. To fight you, Punch. Not because I save you but to save myself as well. I'm not a kind person either.

And that's why in Sonic Prime, Sonic still believe and trusts Nine not because Sonic's too trusting. Sonic's sad not because Nine betrayed him but he sad because Sonic was the one that made Nine become this way.

As a result of what happened, that's why King Gilgamesh chose to walk alone to not let this happen just like what happened to Nine in Sonic prime.

Even though Sonic will end up destroying the world just like King Gilgamesh and Punch will do, Amy still chose Sonic because Amy knew Sonic will always do the right thing. Amy's reasoning is the same as Enkidu's.

And not different why Enkidu, Hakuno and Danny defend Punch and King Gilgamesh like Amy does.

[sakuraswordly]

"In all this world, only one shall be my friend. Thus…not for all eternity shall his worth ever change."

I show some of Peter and Punch because Enkidu's feelings are the same as Peter's. Even Gilgamesh mention that Enkidu and Peter are similler but they are still different. When Enkidu died, he saw Gilgamesh's vision of the past and future. He saw Gilgamesh lose his friends once(As you can see in Sonic Prime) and lost Peter with Punch's sadness behind him. Enkidu sadness finally appears in front of King Gilgamesh and sees with his own eyes how Sonic, Punch and Gilgamesh's loneliness. Enkidu felt regret for the first time that he left them alone.

Enkidu: — Ah. How sinful. I knew he was weak but I never considered his weakness. I knew he was strong but I never recognized his strength. You can’t say I understood him. But he was completely sincere in keeping himself isolated. I left an eternal wound upon his dignity.

Sonic, Punch and Gilgamesh can walk moving forward alone but if their precious friends end up in danger because of them, they will cry inside trying to hide from everyone. Even though they hate tears to show how weak they are, but because Sonic, Punch and Gilgamesh are very sensitive and have golden hearts, you can see a small shed of tears in their eyes.

But Sonic will show his tears more than any other but you can tell how deep down both Punch and Gilgamesh hurt so much. Especially Gilgamesh, even though he can even control his emotions better than both Sonic and Punch but you can see in Fate grand order absolute demonic and Fate extra ccc, that he still can't hide his sadness in front of both Enkidu and Hakuno.