Hello, this is yet another challenge by Black-Tortoise-of-the North. I hope to impress everyone with yet another Ben 10 story. I found this idea to be interesting and I hope fans of the show will enjoy it. Well, here's the first chapter. The story takes place during Ultimate Alien. I love that show than the newer one. Why did they change the animation of Ultimate Alien? WHY!

Disclaimer: I don't own Ben 10.

Chapter 1: Kevin's sister?

There were many things Kevin Levin didn't want his friends to know about him. It is because he held secrets from them that he would block them out of his life at times. Yet, one of those secrets was trying to let itself out through a text message.

Kevin had been texting someone through the ride back from visiting Ben and Gwen's Grandpa Max. Ben was growing curious of whose Kevin mystery texter was. Ben wasn't able to see who it was because he was driving the car with Kevin at the passengers seat and Gwen in the backseat. Although, Gwen wanted to respect Kevin's privacy; she couldn't help feel a little jealous of who ever Kevin was texting.

"So, are we going to get any clue as to who you are texting" Ben grumped as he wanted to know who he was texting

"Nope, not telling you" Kevin said focusing on his phone

"AHHHHH come on" Ben was complaining like a 5 year old boy, who didn't get what he wanted.

"Ben, if Kevin wants to tell us who this person is, then he will tell us" Gwen said "Even if it's a girl"

Even though Kevin knew Gwen was ok with him texting other people, he couldn't help but feel a stinging glare from her as if he disrupted some sort of balance in her system of her life.

"Besides, it wouldn't matter anyways" he shut his phone as he relaxed in the seat of Ben's car.

However, their social life would be cut short by explosion that happened within a bank.

"Well its hero time" Ben called out running out of the car.

Gwen looked at Kevin giving him the 'we are not done with this conversation' face.

"You guys done fighting, there are Forever Knights to fight" Ben looked at them with Gwen and Kevin following close behind him.

Inside the bank, the Forever Knights were stealing gold from the vault of Bellwood Bank.

"More gold for our king" one of them spoke out

Ben and the gang arrived as the knights spotted them

"Why can't you guys steal gold some other night? I have a math test tomorrow" Ben told them.

Uncaring about his education, the Forever Knight charged at Ben and his friends with plasma guns and swords.

This didn't take long for Ben to turn into Four Arms. Kevin rush to where the gold was and absorb its properties to become solid gold in order to fight them. Gwen just simply blasted them with her mana.

The fight raged on for what looked like an hour. Most of the Forever Knight were either down for the count or tied up by the trio. One of the knights had fled from the battle. Kevin looked at Ben and Gwen who had nodded for Kevin to chase after him.

Kevin was rushing into the alley that the guy escaped to. He looked everywhere for where the knight was.

"Come on out you coward" Kevin looked around as the knight was behind him.

However, Kevin turned back long enough to see the knight knocked out by a steel arm that extended itself long enough to hit him.

Kevin sighed as he looked around knowing whose hand that belonged to.

"Nice to see you again, Kevin" the voice smirked

"Kari, come on out" Kevin looked around to see where she was

"O come on you know me so well. You even know my favorite game, hide and go…ahhhhhh" Kari said before Kevin deduced where she was and pulled her from it.

"Kari, what are you doing here?" Kevin growled looking at her

"You weren't answering back to my texts, so I decided to investigate where you were" Kari smirked

"Kevin" Ben and Gwen went to find him as he looked at her.

Without a second thought, Kevin pushed her towards some trash cans in order for him to hide her.

"Hey, you got him" Ben told Kevin

"You alright" Gwen questioned him

"Yea, I am alright, why wouldn't I be alright" Kevin chuckled "I think we should go home"

"O come on, going out to fight bad guys was your idea" Ben crossed his arms "Why suddenly do you want to go home"

"O it's none of your business Tennyson" Kevin growled before a voice appeared behind him.

"Ow, that really hurt my head" the woman got up.

Ben and Gwen saw a woman with jet black hair that extended down to her waist. Her eyes were covered by the hair as her mouth and nose were visible. Her jeans and dark hoodle looked similar to Kevin's outfit.

"Umm, Kevin who is this" Gwen called out seeing a girl behind him

"It's no one" Kevin tried to avoid the subject

"You must be Gwen and Ben Tennyson. My brother has told me so much about you two" She said shaking their hands and giving them a sly smile.

"Sister, you have a sister" Ben and Gwen were shocked at Kevin

"Yea, this is Kari Levin, my sister unfortunately" Kevin said before his sister slapped him upside his head

"Yea, I guess we will be seeing more of each other" Kari smiled "See you at home big brother" Kari smiled more leaving Kevin to be questioned by his friends.

I think this is a good stopping point for chapter 1. Tell me your thoughts on this chapter. Did you like it, did you dislike it? Let me know by your comments and reviews. Hope everyone has a great day.