-Two years earlier-

A Alien is seen speeding down towards Patch. The blue and white blur rushed ahead as he seemed to be panting with his heart rate racing.

"You can make it Y/n. He's counting on you to be there with him." He thought before a quake appeared making the ground split causing the blue blur to trip and tumble across the ground. The blur appeared to be the alien known as FastTrack.  Looking ahead the boy noticed Humongisaur on his back. "Grandpa!" He said gaining the other aliens attention.

"You shouldn't be here!" The dinosaur alien said a green flash appeared showing the boy in his pyronite form.

"And I told you this is our fight." He said as a sudden boom went off behind him turning around the boy went for a sweeping fire attack but was blocked. Feeling a tendril around his waist the pyronite was thrown into a few trees.

The boy stood up before seeing his attacker. There stood Ben's archenemy the alien known as Vilgax. Y/n got up before firing a blast of fire as a slime like substance exited his arm from one of the four hole sticking the alien to the tree.

"What? I can't move!" He said trying to burn through the tree only to successfully burn the wood but not the slime. "WHAT IS THIS?" He yelled angerly annoyed at the fact he can't escape. 

Just then Vilgax was grabbed and thrown far thanks to Humongisaur. Humongisaur looked at the pyronite before sighing. 

"Relax Y/n think of how to escape. Who do you have that can escape from something like this?" After a quick relization Y/n morphed into his Necrofriggian Absolute Zero and phased through the slime.

"Sorry grandpa. I guess I got a little hotheaded." 

"Was that a pun?" He asked making the Alien whistle cold air. 

Just then the silly moment was interrupted as Vilgax appeared and quickly threw his tendrils at the two aliens infused with electricity making the two scream and roar in pain. "I know all of your aliens weaknesses. Nothing you two can do will ever stop me. All thanks to Animo." 

"Y/n....we need to transform...once more." Ben struggled out making the boy screech in pain. 

"Who?" 

"Feedback, Chromastone or Ampfibian!" two green flashes' went off as Ben turned into Ampfibian while Y/n turned into his Crystalsapien form as the two absorbed and redirected the electricity back as blue electricity and rainbow energy making Vilgax block the attack with his massive left arm. Being charged up due to Ampfibian Y/n fired a massive rainbow attack as Vilgax rushed at the two and gave Chromastone a uppercut ending him flying while Ampfibian was sucker punched into the ground. Morphing into another Alien while in midair Y/n's body began to morph as he was covered in armor with the omnitrix symbol appeared on his collar as he summoned a weapon made out of wires. 

"TenTen!" 

(Art by https://www.reddit.com/user/Pluagemask42/) 

Firing his weapons rapidly TenTen summoned his jetpack as he fired his weapons. Vilgax glared at the annoying alien. Opening his knuckled multiple spiked discs flew at the boy as he summoned his two small extra guns on his shoulders taking out each and nearly everyone. One managed to land on the boys face as it  pierced his masked and filled it with Methane making the alien choke as it landed on the floor gasping for air. 

Vilgax went to attack the boy but was double punched by Ben's four arms transformation. Running and laying the smack down four arms sent Vilgax flying a bit. But he was restrained as the alien pulled him away from his grandson. Using the same slime Vilgax restrained the Tetramand. 

Y/n looked at his grandfather with watery eyes as he choked. "Alien that can help out....that's it!" thinking to himself Y/n morphed into his Echo-Echo form. Vilgax and Ben looked at the alien. "Soundwave?" Ben asked as he saw his grandsons Sonorosian form. 

(Art by the hawkdown on deviantart) 

Taking a deep breath Y/n let out a sonic wave as Vilgax and Ben were both hit but it kept getting louder and louder for vilgax due to three more Soundwaves appeared behind him. Bens pain subsided as the original stopped before Vilgax dropped the hero allowing the both of them to back away a decent amount of feet. 

"Y/n why did you turn into Soundwave?" 

"Trust me on this grandpa....I've done some upgrades with my Cerebrocrustacean transformation." He said as the three were being attack by Vilgax.

"What did you do?" 

Slamming on the omnitrix symbol on his head Soundwave began to morph. Ben looked in shock as Y/n's form changed. 

(Art by https://www.deviantart.com/vinyruby/art/Ultimate-echo-echo-1006240043)

"Ultimate Soundwave!" Thrusting his arms out a massive sound wave appeared pushing Vilgax back. 

Ben also morphed into his Echo Echo transformation as the both used their soundwaves to keep him back. 

"You do know that this will drain the Omnitrix?" Ben asked as Y/n kept up his attack going. 

"But I have master control." He countered making Ben nod.

"You really are my grandson." He chuckled before Y/n summoned a couple of discs from his shoulders as they flew towards Vilgax before multiplying around the villain. 

"Sonic Dome!" He yelled as the discs let out a ear shattering sound making Vilgax fall to the ground defeated. Moving towards him Y/n summoned one more disc as all three aimed at Vilgaxs head.  "And stay down." 

Vilgax's eyes snapped open as he quickly grabbed Y/n with his right hand as his left hands pointer finger glowed red reverting the boy back into his human form.

"What? How did you?" 

Vilgax slammed Y/n to the ground making the boy cough blood as Ben went to save his grandson only for Vilgax to use him as a shield. 

"Choose Tennyson. Me or your grandson." He said as Ben had morphed into Atomix. 

"D-Do it." He called to his grandfather but a female voice appeared 

"Claws off my son Vilgax!" Suddenly Vilgax was pushed away from Y/n y a blue laser as he was dropped from his grip. Atomix came and quickly grabbed him as Ben looked at Vilgax and his grandson. Atomix turn to the side seeing his daughter in her Plumber outfit holding one of the weapons grandpa max used against Vilgax.

"Dad?" M/n asked as she looked at the two due to her appearing in the plumber tank.  

"You need to get him out of here. Your brother is most likely worried that you came out here by yourself."

"Kenny can take care of himself. But what about you?' She questioned as Atomix smiled at her. 

"I'll handle Vilgax alone. I got one final trick up my sleeve." He said making her look in shock. 

"But....You know Y/n won't be to happy." She said making him nod.

" I know. But I also know he won't let me down. I mean the kid already has a lot of aliens and he's still younger than me." He chuckled. " Keep his head on straight sweetheart." 

" I will." She said before moving towards the Plumber Tank as she drove off leaving Atomix with Vilgax. 

After gaining enough distance a massive nuclear explosion went off as a mushroom cloud went off as M/n was crying as she drove off. A day since the fall of Vilgax and Ben was hard on the Tennyson family. Y/n was still out as he had to go into surgery due to the damage Vilgax did to him in his human form. After some physical therapy Y/n could crouch and properly roll after having his ribs fractured. Once Y/n found out about his grandpas passing he was in complete denial but when he was shown ground zero of the explosion he knew it to be true. Out of love for his grandfather he renamed his aliens after his and continued to fight for people and secretly aliens alike. Due to him helping the public he was showcased on the news and even some magazines as to who were these creatures saving people. One such case was Water hazard putting out a fire. Diamond head making a few crystal scaffolding to keep a cave from collapsing. Heatblast putting out a forest fire thanks to his fire absorption and even XLR8 putting an end to a highspeed chase to name a few. But there were a few times where he would have issues with the watch as his Ghostfreak alien named Haunts had broken free and tried to control his body but was stopped by his mother as she used the nullvoid projector to lock him in a empty void. Along with being stuck in his alien forms for a week each allowing him to master the specific alien for about a year. Allowing him to master about fifty-two aliens. Y/n had also mastered his ultimate forms.

But there was one thing that Y/n had to do to put an end to. A rouge Celestrialsapian out in space. Thanks to the help of Starbeard another Celestrialsapian, Y/n and Starbeard stopped the rouge as he turned to Alien X. But due to it's power Y/n couldn't risk losing the watch along with his aliens, god forbid Alien X. So the hero put Alien X in lockdown due to it's raw strength. Having his mother hold onto a key his father made for the Alien--they both promised to unlock the DNA in times of great desperation. Like the Celestrialsapian. But for now the boy had hoped to relax in college away from alien work after he had gotten accepted into Beacon Academy. Oh how wrong he was.