It was time, You vs Adam, which brother will prevail?

You: I got this!

Adam: You sure because I'm not losing!

You: At least Dabi isn't going to burn us!

Adam: Yeah we made it to the finals!

Then an announcement goes off telling the two fighters to enter the arena

You: You ready?

Adam:

You: That's the spirit!

You both go to the arena opposite each other as Midnight begins the fight

Midnight: Begin!

Adam grabs his sword, Darkness and dashes at you while you equip Death Strider, you both dash at each other and clash which caused a shock wave, exciting the crowd

Iida: What is this power?!

Ojiro: This is insane!

Midoriya: We never saw this from them before!

Bakugou/Todoroki: Has he been holding back against me?!

You: Oh so we're getting serious now?

Adam: Not yet remember?

You: You're right!

You both backed off and readied yourselves as you begin to clash and parry each others attacks at high speeds

Mic: WOOOOOW THIS IS SOMETHING YOU WOULD NOT SEE EVERY DAY! A FULL ON FIGHT BETWEEN TWO BROTHERS!!!!!

Aizawa: Lord shut this man already

Fubuki: Win Y/n!

Tatsumaki: Yeah!

Saitama: I wanted to fight...

Genos: It's ok master Saitama

Bang: You're not aloud to fight in a fight between heroes in training

Back with you

You: Damn we're pretty even don't you think?

Adam: Yeah but the fact that you barely had any time to recover is shocking!

You: I recover quick you know!

Then suddenly Adam parried your attack and countered by spin kicking you in the jaw as you almost hit the out of bounds area

Kaminari: He almost got him!

Tokayami: It seems everyone wants to force him out of bounds

Shoji: I wonder who will win

Jirou: It's Y/n!

You: Damn Adam! That was slick of you!

Adam: I'm a natural at those!

You: Hey I do the same!

Adam: True that but I'm better at them!

You: Wanna test that theory?

Adam; Nah I'm good

You suddenly disappeared with your fire quirk behind him but he was ready as you swinged but he blocked it and kicked you back

You: God dammit it!

Adam: I'm a genius!

You: That's my line!

Adam: Since when?

You: Since now!

You used your void quirk to warp infront of him but he expected you were behind him so he attacked from behind but when he realised you weren't there he realised he fucked up

Adam: Oh.....shit

You: Gotcha boi!

You engulfed your right fist in flames and left fist in Void energy as you unleashed an endless barrage of punches as he couldn't take it, not even his adrenaline could save him

You: Give up!

Adam: Not yet!

He then released all of his energy and explodes the area around him as you jumped back

You: Oh damn!

You look to see he transformed into his other form which stood at 7ft

You: So we're doing this now.......alright!

You engulfed yourself in Void energy as you transformed into your Void Trigger Form

You: Alright!

Mic: NO WAAAAAY! BOTH CONTENDERS HAVE TRANSFORMED! BUT WHO'S TRANSFORMATION WILL PREVAIL?!

Adam: It will be me!

You: Nien!

Bakugou: FUUUUCK!

Todoroki: -_-

Midoriya: Things are going to be heated! *foreshadow*

Adam charges at you and tries to stomp you but you were quicker as you dodge and gave him a right hook

You: Suckerpunch!

But Adam wasn't fazed as his defence has increased

You: Ah crapbaskets

Adam: My speed is also increased since I've been training as well

You: 0_0

Adam: :D

He slammed you to the ground with his fists as you felt the pain more due to not fully recovering

Jirou: Y/n!

Adam: Sorry Y/n but I'm winning!

You: No way!

You warped behind him and spin kicked him away while throwing multiple void orbs at him, he recovers however and tanks the orbs

Adam: Is that all you got?

You: No but thank you for asking!

You summon your other sword Chaos

You: I'm just getting started!

Adam: Then I'll do the same!

He gets out his sword

Adam: Get ready!

You both dash at each other and clash once more but with more intensity

Aizawa: This is close

All Might: No way!

Endeavor: *mutters* Now I know why that boy defeated Shoto

Bang: What was that Enji?!

Endeavor: Nothing old man!

Then suddenly you break Adam's sword and impale him

Adam: Gah!!!

You: Sorry about your sword Adam

Adam: It's alright I can summon another one

You: Oh ok-wait what?!

Adam smirked as he did summon his sword back and swung it at your side as you rolled along the floor while your Void Trigger Form dispersed

Adam: Really I should be saying sorry

He takes out Chaos and throws it away so you can't go grab it

Adam: You probably can't move so I win!

Midnight: Y/n is unable to battle, so Ada-

You: N-not y-yet!

Adam: U wot m8?

You slowly got up with the remaining strength you had left and moved slowly to him

Adam: Oh? You're approaching me?

You: *laughs* God dammit Adam

Then suddenly you felt the urge to explode as you were surrounded in flames stronger than before

Adam: This power!

Everyone was beyond shocked you could still move

You: I'm never done until the last moment!

Adam: Ooh this is making me excited!

But that was bad for Adam as suddenly a Column of fire surrounded you

Adam: ?

And then......you transformed

Adam: 0_0 HOOOOOLY SHIIIIIIT!

Mic: WOOOOOW! Y/N L/N HAS A NEW FORM! IS THIS HIS TRUMP CARD?!

Aizawa: Y/n......

Adam: Alright Round 3-

More like round Y/n since the first thing he did was grab Adam by the face and slammed him with more aggression while roaring

Adam: Nani?!

Then Adam tried hitting you with his sword but it broke upon contact

Adam: 0_0

He realised he was fucked as you grabbed him and slammed him again, then you clenched your fist and punched him hard in the gut

Adam: !!!!

Adam got up and punched you multiple times but it was futile as it did nothing to you

Adam: Y/n calm down!

Rule number one! Don't tell a devil to calm down! Why? Well then the Devil beats the shit out of you, just look at Adam

Adam: Someone help!

Then all of a sudden before Y/n was going to claw at Adam, Midnight managed to put you to sleep with her quirk, which took time since you were resisting

Midnight: Uhhh Y/n L/n loses due to unnecessary violence so Adam L/n is the winner!

Random person: Seems legit

Adam: Heh...nice save

All Might: What was that?

Genos: I don't know....

Fubuki: Y/n......

Bang: 'I know what it was...but everyone here does not need to know for now'

Adam: God damn......Y/n you bastard.....leaving me in the dust like that

Then Adam passed out as Class 1-A was wondering what just happened......

Alright let me explain somethings.....Y/n can use his fire quirk on the bottom of his feet to  boost him, the same way like Shinra's Adolla burst from Fire force, also the fire teleport is the same way Scorpion does it like I said before and the Void teleport is actually warp so you just basically blink to a close ranged location, also you don't completely dissappear as it's like a sidestep

Also the reason the new form wasn't the one in the bio was  ease that was your Devil Trigger from with no control what so ever..but the one in the bio is the controlled version which will come soon

Finally Y/n's sword is called Devil Strider but He doesn't know that, instead it's actually called Death Strider so he will find that out soon as well