Note: Star vs the Forces of Evil belong to Disney and Sonic the Hedgehog belong to Sega. I don't own anything. once again just to remind your readers, this this my first fanfiction, so my writing will not be perfect. I hope you enjoy the story, and let's continue where we left off. Also I updated the chapter selections, now the Chapter Titles match with the actual chapter from prologue to this current chapter. I just learn how to edit the Chapter Titles.

Sonic and Star in Adventure in Mewni
Chapter 6 The Seth Encounter

Our heroes followed Pony Head, one of Star's best friends, to her room in the cloud palace to get the Chaos Emerald as our team of heroes explain to Pony Head about Dr. Eggman and the recent events.

"Oh dang B-fly, you must have been really busy since this morning. I'm surprised that you guys managed to hold your own, ok like after I give you that emerald, I'll wake my dad up so we can like defend ourselves against whatever is Eggman guy throw at us."

"Well Pony Head, we better hurry because according to this transmitter, the Wing Fortress has already entered city air space and will arrive in 12 minutes" said Tails as he hold the transmitter which show a hologram map with the Wing Fortress on it moving towards Cloud Kingdom. Then Marco pull up his phone and to see the news, and Tails is right. An giant flying battleship made out of light brownish metal with a few parts being red or silver flying high over downtown Echo Creek using various circuits and engines can be seen adorning the ship's walls. The site of this flying ship has caused a panic in the city.

"And it's already over the News, just like when our worlds were cleaved together 3 weeks ago."

"That was quick, I guess Eggman does not waste time."

"That's basically Eggman's style" pointed out Sonic, "he shows off his army to send fear to send a message but they're not invincible."

"I hope you right, hedgehog man because I don't want my home to be a mess again like 3 weeks ago." said Pony Head remember that helicopter that almost crash into Cloud Kingdom when their worlds were cleaved together.

Finally, they reach Pony Head's room and then Star open her friend's lilac/lavender door to find a surprisingly elegant room. Game consoles connected to a wide screen tv which face Pony Head's bed which is a mix of purple and lilac and right next to the bed is a heart shape mirror with light bulbs built in siting on a large drawer which a cyan Chaos Emerald sit at the center on top of the drawer. Star walk up and grab the Chaos Emerald and place it in her star-shaped bag with the other 3 emeralds, and once again Star felt that oddly familiar feeling but this time it's stronger before that feeling quickly faded away. Then Star turned to Pony Head and said "now let's wake King Pony Head.

Suddenly an explosion happened outside the palace which forced our heroes to use Pony Head's bedroom window to see what's going on and saw large bee like robots in the sky and Septarian Warriors are on the attack.

"They're already here?"

"Ok, Tails, you help Star warn King Pony Head, and we're head out to by time." Said Sonic as he opened the window and rush through to fight the attackers followed by Knuckles.
"You're so lucky my window can be open, otherwise you be a boat load of trouble." Yelled out Pony Head as She, Star, Marco and Tails rush towards the throne room to find King Pony Head.

Sonic and Knuckles rush in the battle Buzz Bombers and Septarian lizards while helping out the locals as Wing Fortress can be seems flying besides the edge of the kingdom launching for flying robots.
"Knuckles, we need to get to Wing Fortress, if we take that out of the picture, we could stop this invasion." Pointed out the blue hedgehog just after rescuing another group of pony head locals from a small group of robots. Knuckles agree with Sonic and rush towards Wing Fortress, unaware back at the front gates of the palace, a portal open up and Seth come out followed by Eggman in Big Arms, a modified Egg Mobile with big robot arms.

"If the reports from Buzz Bomber 887 are correct, Sonic and Knuckles will head towards Wing Fortress to try to take it down, which means they left their other friends all alone in this palace with their Chaos Emeralds." spoke Eggman through the built in speakers as he pilots Big Arms

"Let's slit up, you with go and deal with them in the palace, I'll deal with Sonic at Wing Fortress, and once this is over, we'll have all 7 Chaos Emeralds." Then Eggman flew away in Big Arms to face Sonic leave Seth to handle his part of this mission and rush in to search for the emeralds.

Meanwhile Tails, Star, Marco and Pony Head reach the throne room where Pony Heads's father, King Pony Head, who is a giant unicorn head with a neck with, light teal fur, a deep blue mane and beard, bushy eyebrows, dark blue eyes with gold stars for pupils and a teal striped horn and wore a golden crown with a purple jewel in the center. The king of the pony heads stares out the large windows in his throne room watching the chaos in his cloud city as Septarian Warriors and flying robots attack the unexpected citizens. He heard someone entering the throne and turn to saw his daughter, Star and Marco, and a yellow two tail fox.

"Sweet heart." yelled King Pony Head in a bold, commanding voice as he hovers towards our heroes wanting a explanation. "I just woke up to a bunch of explosions outside and I..."
Before the King could finish, Star cut in off and explain "King Pony Head, your kingdom is under attack by a mad scientist named Eggman and a Septarian named Seth, I'll explain more later, but right now, your people and two of my new friends who are doing their best to help, need your help your majesty."

"Did you just say Seth...the last time I hear that name was before your mother began queen."
"It's true your highness, and if we don't stop them, they will destroy everything."

But before the King could do anything Seth flew out of nowhere and kick King Pony Head hard enough to sent the giant head flying and crashing into the throne, knocking the King out.

"NO" Yelled Pony Head as Seth turned to face our heroes and said, "Star Butterfly and Marco Diaz, so you are the ones messing with my army of Septarian Warriors."

"I am Seth of Septarsis, and even without your magic, you butterflies are always getting in the way."
Pony Head flew in to fight Seth for harming her dad but only to get slapped by Seth which surprisingly launch Pony Head in mid-air and crash into one of the throne room's stone pillars and then Pony Head fell to the floor unconscious but still alive. "Stupid pony heads"

"Oh no..."yelled Star as she face Seth and Said, "now you took things too far Seth.

"Oh you little wingless butterfly, I have only just begun, either you give me your Chaos Emeralds or else we'll do things the hard way."

Star's only response is karate kick at Seth and bounce right off, pushing Seth back alittle. "Tails, hide" as told, Tails ran to hide.

"The hard way it is."

Back to Sonic and Knuckles, they reach the edge of the Cloud Kingdom. The only thing standing between them and Wing Fortress, which is now closer but still a very far distance, is a open sky, 6,500 feet over the ocean. Luckily Sonic has an idea as he noticed a fleet of Turtloids, a large turtle like flying robot that possess two gray jet engines on their backsides, metallic head and front arms with a smaller turtle robot riding on top standing on two back feet and holding a rail, fly towards the edge of the kingdom.

Sonic jump off the edge and use his homing attack to hop across one Turtloid to another to reach Wing Fortress. knuckles who see what Sonic is doing, followed the same way but gliding. Eventually the hedgehog and echidna reach Wing Fortress, the flying ship is the same as it was when Sonic and Tails chase Eggman as the mad doctor escape to the Death Egg back on Mobius, so it was too difficult for them reach the front of the fortress but before either of them break into the airship interior to reach the bridge, Big Arms show up and began attacking our heroes.

"Oh no you do." yelled Eggman through the speakers as he tries to land a hit on his enemies and Sonic spin jump and hit the cockpit of Big Arms.

"Well it isn't Dr. Eggman who got his butt kicked by a girl the last time I saw you." Joked Sonic which rattled Eggman up and said, "that doesn't count, if she and her boyfriend didn't decide that fight, I won't have won."

"You mean I'll still kick your butt and knock those Septarian Warriors."

"Always the wise guy as usual Sonic, but it will not matter anymore once my allied Seth get the remaining emeralds from your friends which should be happening by now."

Meanwhile back in the throne room, Tails hide behind a pillar as he watches Star and Marco fight Seth and even though they are holding well on their own, Seth has more experience, faster and stronger.
As he watches, the fight reminded Tails of the first time he and Sonic encountered Infinite which the masked jackal defeated Sonic right in front of him using the power of the Phantom Ruby, a stone that creates convincing illusions and maybe more. But he remembered the conversation with Sonic back on Starfall Islands about not being a burden and Sonic reminded him about the time he stopped Eggman from blowing up Station Square and sabing Sonic from that trap set up by the Deadly Six back on the lost Hex on Mobius.

"No, not this time, I can't grow into my full potential if I just stay here and watch, I have to help Star and Marco but how?" Tails think to himself as he work on his courage, "I can do this, I stop that missile from destroying Station Square, I saved Sonic from the Deadly Six twice on the Lost Hex, I fought Eggman on the Space Colony ARK and won. I can do this."

Tails spotted Pony Head's unconscienced...head and using his twin tails to fly over the fight without getting notice to Pony Head and try to get her to wake up, and after a few tried, Pony Head slowly woke up.

"Oh, wha...what happened, did I win?"

"No but I have a plan to help Star" then Tails whispered to Pony Head his plan.
"Ok fox dude, let's do this."

Back to Star and Marco, still fighting against Seth and their backs against the wall, our two heroes are about to run out of energy to continue to fight.

"Give up already," hissed Seth, "you are completing lack of experience, I'm stronger and that hedgehog and his friends are not here to save you now. Those emeralds are mine."

"Are you sure about that?" Yelled Tails as he holds on to Pony Head's neck to fly over Seth, then dropped and jump off Seth's head before the Septarian leader could look up, then Tails spin dash towards Seth from behind and forced him to fell backwards onto the floor and then Tails spin jump, hitting Seth in the stomach before rushing back to Star and Marco giving then a high five.

"Thank for the help Pony Head, I guess this is hold Sonic when I hold him in mid-air."

"No problem fox buddy, and that stunt we pulled was amazing, let's do that again some other time."

"Yeah Tails that was amazing." complemented Star "Tails for the win."

However without knowing Seth quickly got back up, snatched Star's bag, the bag with our heroes' Chaos Emeralds and ran into the hall.

"Oh no the Emeralds, Stop him!" Yelled Marco and our heroes chase the Septarian leader.

Back to Sonic and Knuckles, their fight with Big Arms was about over, as Sonic lay the last blow on the cockpit and the modified Egg Mobile exploded leaving the still functional Egg Mobile and cockpit with Eggman in it the only surviving parts of Big Arms. However one of the robot arms crashed through into the Wing Fortress' Bridge and exploded causing a chain reaction of smaller explosions all across Wing Fortress and began to lose attitude and slowly began to fall towards the ocean before.

"No my Wing Fortress, my Big Arms, I just rebuilt these two, you'll pay for this once I creates my Solarian Robot Army." Then Eggman piloted the Egg Mobile towards the cloud palace.

"Knuckles, we need to get back to our friends, they're in trouble, can you glide us back to the Cloud Kingdom?"

"I'll give it a try?" Then they ran off the Wing Fortress and Sonic grab Knuckles' hands while the echidna carefully glide himself and Sonic safely back into the Cloud Kingdom and rush at top speed to their friends.

Back at the front gates, Seth rush out and meet up with Eggman as the Egg Mobile descended and open the cockpit to meet the Septarian Leader.

"We finally have all 7 Chaos Emeralds Dr. Robotnik?"

"Excellent, soon my robots and your warriors will be as strong as Solarians, now let's open the portals can call in a retreat."

"Eggman" Sonic yelled and he and Knuckles rush in from behind the Egg Mobile, while Star, Tails, Marco, and Pony Head ran out from the palace behind Seth and Star yelled "Seth." Then Seth jump up and grab the Mobile's side as Eggman raise his mobile with Seth standing on the wing to avoid captured.

"You're too late, Sonic Zeros, we have all the emeralds and soon, when the Master Emerald restore the wand, I Dr. Ivo Robotnik while use it to create my own army of Solarian Robots?" yelled Eggman in triumph and revealed their evil plan knowing that there's nothing our heroes can do at this portal.

"Wand? what wand and you're planning to create your own Solarian Warriors?"

"You know very well Butterfly" hissed Seth, "the royal family wand which you and your family once used and now it's in our hands."
Then Star remembered, the last time she saw the wand, Marco was using it in the Realm of Magic during his fight with Tom who was somehow under the Realm of Magic's control.

"Oh no... but it was destroyed along with the Realm of Magic?"

"Oh yes but like me, the wand survived with the help of a Chaos Emerald that appeared around that time you destroyed the magic."

"You were there when it happened?"

"Of course I was there, before your grandmother was killed by Toffee, she managed to banish to the Realm of Magic where I was trapped for years and due to my Septarian body I didn't lose my memories just like how Toffee kept his memories as he slowly destroyed your magic."

"Seth was trapped until the Chaos Emerald that appeared in that realm teleported itself back to Mobius with Seth and the wand to Scrap Brain Zone on South Island where I found him in." Eggman chimed in "and told me everything about your world, your wand and about Solaria and her Solarian Warriors and soon my plans will be complete. HAHAHAHA"

Then Eggman dropped a smoke bomb and exploded in a cloud of smoke which our villains used to escape without a trace leaving our heroes with more questions.

That's the end of the Chapter, I didn't want to make the chapter too long. Star vs the Forces of Evil belong to Disney and Sonic belong to Sega. I don't own anything. my writing is not perfect and I'm trying my best to improve. In the next chapter, our heroes will discover the location of Eggman's secret base while Dr. Eggman finish the final adjustments, but Seth has over plans. I so happy that people like you are giving my first fanfiction a chance to read and I mor happy that you like that is going so far.