After leaving Goku back at the compound, Steve left with Sam for something he didn't tell his son or Tony about. After he left, Goku stays with Wanda, Pietro and Vision and did barely anything. He even watched a special moment when both Wanda and Vision interacted with each other, in a kind gentle way. It kinda made his heart felt warm that maybe Wanda has know have someone special to her, and he doesn't interrupt them in any way.
However, the Twins and Vision never told him about what's going on, since they still agreed that Goku shouldn't know about the Sokovia Accords, since he along with Thor saved the entire city from becoming a meteor. It would seriously offend him in some way, and he was just doing his job in protecting Earth.
Goku left the Compound to his normal training area, but this time he's going to do something different. He's going to see if he could go beyond a Super Saiyan God and become even stronger.
He lands on his training area and starts to warm up a bit, before starting to charge up.
Goku: AAAAAAAAAAAAAAHHHHH!
Goku turns into the SSJG, but continues charge up even more. He yells as he powers up farther than he could imagine. The ground begins to shake fiercely ad Goku's aura grows larger than before.
Goku: C'mon! Times 5!
He charges up even more as he starts to see a more orange fiery aura around him, while still inside the red aura. He charges up even more, as the ground begins to crack faster and harder than before.
Goku: Come on, kid! You can pull through! Just...a little...more!
He clenched his fist as he squats for a bit, before yelling.
Goku: TIMES 10!
His aura flares around like a bit fiery tornado up to the sky. The Earth itself shook violently from his power.
*In Germany*
Steve, Sam, and Bucky are hiding from the Authorities, as they wait for Clint to return with Wanda, Pietro and Sam's chosen recruit to appear. Then, the ground started to shake violently.
Sam: What the hell?!
Bucky: Why is the ground shaking?!
Steve: I don't know, but I hope it isn't an earthquake!
Then he realized something.
Steve: It's Goku.
Sam: He's the one causing this?!
Bucky: Why is he doing this?!
Steve: Must be measuring his power, and I don't think he's close to full power.
*at the Joint Counter Terrorist Centre*
Everyone in the compound was trying to hold on to something as the floor was shaking like an Earthquake.
Ross: Stark, what's going on?!
Tony: I don't know, but it's not me, okay?!
Rhodey: How's the earth shaking like this?! There's no earthquake detected around here!
Natasha: I don't know, but whatever it's coming from, it must be powerful!
*back at the Avengers Facility*
Clint, Pietro, and Wanda were leaving the facility after taking care of Vision to go and meet with Steve and the others. Then, the ground started to shake violently.
Clint: What the?!
Pietro: что за хрень?! (WTF)
Wanda: Why is the Earth shaking?!
Then, they see a huge beam of fiery red light coming from far away up to the sky.
Pietro: It must be Goku!
Clint: He's making all this happen?!
Wanda: I'm not sure, but if it is him, his power is far more than we expected it to be!
The the beam starts to shrink as the ground slowly stops shaking.
*back to Goku*
When it starts to fade, it reveals Goku with his hair standing up than before and he's surrounded by fiery orange aura around his body, while the red aura was around both him and the orange one.
Goku: This...is...farther than I expect it to be. It's amazing that I managed to be more stronger than what I believe to be.
Then, after a couple of minutes in that form, his aura disappears and he went back to base form as he goes down to his hands and knees, exhausted.
Goku: *breathes deeply* Well... that...was...quick. But, I'll manage to master it soon. It think it's getting late. I need to go back to the compound.
He stood up and uses instant transmission to go back to the compound. But when he reappears, something was wrong. He couldn't sense Wanda, Pietro, and Vision around the building.
Goku: Wanda? Pietro? Vision? Where are you guys? It's this some sort of prank? If it is, I'm too tired for jokes. Now, come out or I-
He cuts off because he sees a giant hole on the floor. He goes to check on it, only to see it was far more deeper that he thought.
Goku: What happened here?
He goes around the building, looking for anyone inside, but couldn't find anyone. But then, he starts to feel tired, due two using almost all of his power.
Goku: Dang it. I'm too tired for this. I need to rest for tomorrow.
He goes inside his room and quickly lays on the bed, immediately going to sleep, due to exhaustion and overuse of his power.
*next day*
Goku slowly starts to open his eyes as he begins to wake up. He gently begins to sit up and robs his eyes to get the sleep out of him. He gets off the bed, until he noticed something odd.
Goku: What the?
His pants fell off as his shirt was sagging a bit as it was loose. He looks at the mirror near him, as his eyes widen in shock.
Goku: How did I-
His body becomes thinner in frame and build, like he lost a few pounds. His hair stood up slightly but was still in it's natural color.
Goku: How did I turn out like this? This is something that I experienced when I'm in my super saiyan God form.
He starts to think about it.
Goku: 'Is it because my body made the changes to me when I went full power, yesterday? I don't know, but that might be the case'
Goku takes off his clothes since there too big for him now, and uses clothes beam to make himself a new outfit. He choose something traditional, like a normal fighting gi with blue wristbands and grey boots.
Goku: This looks nice. Nothing beats like using something original. Now, I need to Wanda and the others to find out what's going on.
He grabs his scouter and checks on his power level, but realized he's only 50% percent of his full power.
Goku: Dang it. I'm still not fully recovered. But I can still fly, so it won't be a problem.
He gets out of the building and flies off to find everyone, until he stops and realized something.
Goku: Seriously? I forgot about Instant Transmission. I can find them easily.
He puts his two fingers together and teleports to find his father and the others.
*later*
Only to reappear in New York on top of the original Avengers Tower, which got him confused.
Goku: What? I didn't sense dad here in New York, then why did I teleported here?
He wonders why's his Instant Transmission got him here, and why didn't it take him to where the others are. He decided to do it again. Only this time he teleported on top of the Statue Of Liberty.
Goku: What?! What is going on?! Why is my Instant Transmission not working?!
He tried it again, only this time he reappear in the facility that was in the beginning.
Goku: What the Fuck?!
He's now frustrated. His Instant Transmission wasn't working and he doesn't know why is this happening.
Goku: Forget it! I'm flying! I don't know why my I.T isn't working, but right now I don't care!
He flies out of the facility and through the woods to find his father and the other Avengers. He continues to fly, until he feels something off: He was going down. He tries to get back up, but ultimately, he crashes down on the ground, creating a crater as he goes through the ground.
He stood up and shakes the dirt of him and spat out dirt that got into his mouth.
Goku: What's wrong with me?!
He can't teleport, nor fly correctly. What is going on with him and why? Goku ponders a bit, until realizing something.
Goku: Could it be what I did the night before? Plus, my Ki isn't working well compared to yesterday. I must've developed a Energy Disorder. Which probably explains why my instant transmission and my powers aren't working well.
He's now conflicted. He has to go find his father and ask what is going on, but he recklessly used up his ki and he's now a sitting duck. What can he do, now?
Then, an idea came up to his head, realizing something.
Goku: I forgot! Tony also built in some rocket boosters on the legs of my suit. I don't know why he did it, probably out of habit.
He activates his suit as it materializes around him. He then turns out his rocket boosters on his legs (like Optimus Primes from AOE and TLK) and floats for a bit, until fully got the hang of his temporary style of flight.
Goku: Alright. Now to find dad and the others. Okay scouter, tell me were they are now.
The device detects their location as Goku follows the directions it was telling him to go.
*later*
Goku was flying through the sky, looking to find the Avengers as he goes through the Pacific Ocean, and into the Europe. Then, his scouter tells him that it found them.
Goku: Their in Germany? Where? *he sees the city the device tells him* In Schkeuditz? Why are they there?
He doesn't understand why they are in Germany as he continues flying to Schkeuditz to figure out.
*At the Flughafen Leipzig-Halle Airport*
Goku finally appeared in the airport and he lands on one of the hangers, only to get shock by what he's witnessing. Team Cap and Team Stark are fighting against each other. Steve and Bucky need to get out of the airport to catch a Quinjet to catch Zemo in Siberia, while Tony has to catch Steve and his team, since they went against the Accords wishes.
After a long Civil War, with Clint returning from retirement, Spiderman, Black Panther, and Antman, Steve and Bucky managed to fight through Tony's team and made it to the Quinjet. Goku was shaking his head in denial, not believing on what he's seeing, and decided to stop this at once.
Antman went giant man to distract team Stark so Steve and Bucky can go to the jet as toys around the opposite team. As he was fighting off the others, he gets an unexpected guess.
Goku: *appearing in front of him* Wow you're one big dude!
Scott: What?! A kid with rockets in front of me?!
Goku: Hehehe. Yep, that's me. Also, don't worry this won't hurt a bit.
Scott: What-
Goku punches him in the head, making him fly off his feet and crashing down on a plane. Goku looks down at the fallen giant, as he shrunk back to his normal size.
Goku: So that's how he grew bigger. Interesting.
His scouter detects something as he turns and sees Wanda on the floor and goes to check on her. He goes down and knees near him and puts her head on his lap.
Goku: Wanda. *shakes her a bit* Wanda, are you alright?
Wanda starts to slowly open her eyes, and sees the young boy's face, making her eyes widen.
Wanda: Goku? What are you-?
Goku: No, I should be the one asking the questions. Why are you guys fighting each other? What is it that you can't tell me?
Wanda: *looks away* I'm sorry, but I can't tell you.
Goku: Then I guess you left me with no choice.
He puts his hand on her forehead, and slowly starts to see the events unfolding in front of him: From him leaving to blow of steam, to the discussion on the Accords, the disagreements between each Avenger, and finally the agreement that Goku should bot know about this.
After that, Goku being unhappy was understatement; He was PISSED! He stood up as he sees the Quinjet flying out of the hanger as Tony and Rhodey chased it. He activates his rockets and flies off.
Wanda: Goku, Wait! Come back!
Goku flies his way, joining the chase as he was behind Tony and Rhodey. Later, Sam joins the chase, though shocked that Goku was there.
James: What the-Goku?!
Tony: What?! Goku what are you doing here?!
Goku: Why didn't you and the others tell me about the Accords?!
Tony: We didn't want you to feel mad that they wanted the Avengers to be supervised after the Lagos Mission!
Goku: I saved a couple of innocent lives and this is the thanks I get for that?!
Tony: You don't understand what's going on here, Goku! Now back off!
Goku: Go to Hell, Stark!
Suddenly, Goku turns his head as he sees Vision's attack beam being dodged by Sam, and it's closing in on Rhodey. With no seconds thoughts, he quickly moves left and bumps Rhodey away, and bracing himself for the impact.
The blast hit him on one of his rockets and in his back, and since he was still fatigued from using his power, he could stop himself as he starts to fall rapidly to the ground.
Sam/Rhodey/Tony: GOKU!
Sam and Rhodey went down to catch him before he hits the ground, as Tony joins in. Goku couldn't move, since he was still stunned by the blast as he closed his eyes. Sadly, they didn't catch him as he lands hard on the ground and everything went black.