The captured Eggman has no choice but to take his captors to his base. 

Y/n is carried by Erwin.  While Amy and Sonic keep a close eye on Eggman. 

Once inside.  Y/n was put onto an operating table. Robots were summoned and got to work.  

Eggman: There. The robots can handle the rest. 

Erwin: Then I have no further need for you.

Erwin grabbed Eggman from behind and went to rip his throat out.

Sonic spin-dashed into Erwin, sending him to the right.

Erwin: *growls* You little.

Sonic: We need him. If something goes wrong, he is the only one that can fix it.

Erwin: Fine. I see your point. But he's lucky to be breathing. 

Erwin goes to a chair and takes a seat.  

Hours go by and the surgery is finished, removing the suit from Y/n.

Eggman has to be crafty if he wants to survive. He pushes some buttons and Shadow androids pop out from the ceiling.

Erwin sighs and gets up.

The trio begin to fight the androids as Eggman makes his escape. 

Erwin scraps android after android. 

Afterwards he enters the operating room and sees an unconscious Y/n on the table.

He walks up to Y/n. 

Erwin: Brother, even though we shall fight and kill one another. We will still be family, no matter what happens.   

Amy walks up to Erwin.

Amy: You shouldn't keep fighting.  You and Y/n can work out you're differences, and really be a family.

Erwin: You know nothing! You don't understand why I must do what I am doing!

Amy: I know what it's like to lose family! And that's enough for me to tell you that what your doing is wrong! 

Erwin looks at Y/n.

Erwin: Take care of him until he recovers. Tell him to meet me where this all began.  Let us see if he found his resolve.

Erwin walks away.

Days later Y/n wakes up in a familiar setting. He is once again in Vanilla's house.

Y/n gets up and walks to the kitchen. He sees Vanilla watching dishes.

Vanilla hears him walk in.

Vanilla: Hello again. 

Y/n: Thank you again,for housing me.

Vanilla: I can't turn away someone in need. 

Amy walks in.

Amy: Your awake!

Y/n turns to face her.

Y/n: I was a fool. Forgive me.

Amy: Don't mention it!

Y/n: *sighs* I should have known better than to assume that such a man would help me for a fair price.

Amy: Well...you don't know Eggman like we do. And it must feel like you are backed into a corner. But that doesn't mean you have to do this alone! Sometimes we lose the first time around. But we always win in the end.

Y/n smirks.

Y/n: Glad to hear it.

Amy: Erwin said something, before he left. He wanted you to meet him where it all began.

Y/n: I know where that is. It isn't just for some final battle he has imagined. It is a defensive position. If Eggman attacks, then he can use the lab to force them to adapt to a new environment. Every single one of our people knows that lab like the back of their hand. 

Amy: Well what are we waiting for? And don't you even think of telling me you will go alone. That went terribly last time.

Y/n: I can't argue with that.  Very well.

Sonic appears suddenly in front of Y/n.

Sonic: Sounds like a great party. Count me in!

Y/n: No matter what, we can't let our enemies obtain the chaos emeralds. And I assume Eggman will be watching our fight with intrest.  But in order for me to claim leadership of our people: I will have to use my full power.

Amy: You've been holding back this whole time?!

Y/n: Yes. Our people have access to another form that we can take in order to be more like the dinosaur half of our DNA. It will increase out strength and speed. However it can take a toll on us mentally and physically over time. 

The trio head to the site of the lab. It has an entrance that leads underground. Sentries that were placed outside notice them and one runs inside.  It only takes a few seconds for Erwin to exit with a sizable entourage.

Erwin: Brotherrr. How nice to see you alive and well.

Y/n: I have come to challenge you.

Erwin chuckles.

Erwin: I suppose in such a short time, we have been through a lot haven't we? Very well then. Let's go all out!

Erwin's and Y/n's bodies begin to contort and shift as they grow larger than a skyscraper and their whole bodies shapes to that of a massive monster with sharp teeth,  the head of a tyrannosaurus, claws as sharp as knives, a long blunt tail and feet with claws. 

The two stare at one another for a moment before they launched their punches at each other. The fists collide with a loud and solid thunk.  The two begin to trade blows back and forth, at first their speeds seemed slow. Then they began to build momentum and their fists flew at each other faster and faster.  With every solid punch whoever was hit took a step backwards. Suddenly Erwin kicked Y/n who stumbled backwards into a mountain. Erwin didn't let up the attack and went for another punch. Y/n dodged and slammed Erwin's head into the mountain, repeating this action three times.

Erwin managed to stop him the fourth time and slammed the back of his head into Y/n's nose which made him let go.  Erwin turned around quickly and hit Y/n with an uppercut. Y/n stumbled backwards before regaining his composure and delivering a headbutt to Erwin who roared in pain. 

The fight continued on for some time until Erwin punched Y/n just right and the fist into the chest of Y/n. Y/n roared as he grabbed Erwin by the wrist. Erwin tried to pull his fist out to no avail. Y/n then delivered his own punch which also pierced Erwin's chest.

The crowd below looked on in shock as Y/n then kicked Erwin down, the large body falling hard onto the ground. Y/n stood still as anyone could hear his pained breathing. Erwin began to get smaller and smaller

Erwin is back to his human form as he struggled to breathe. Y/n turns into a human as well and stumbles towards him.

Y/n: *pants* I...win.

Erwin smirks.

Erwin: You...done...us all...proud.

Y/n: I give you...*coughs* The same fate you gave me. I exile you. If you learn...*falls to his knees* to coexist with humans. You may return.

Erwin struggled to get up but managed to do so. 

Erwin: Very well. But perhaps one day. I will do what you have just done to me.

Erwin stumbled away. Y/n smiled. For now the fate of his people is secure. But that does not mean he will not have new challenges to conquer.