(Some elements come from Undertale/Glitchtale)(Evil and op OC's recommended) Pov: You killed his friend while fighting

Amber: *eyes were red and had a knife in hand* ..

(btw when you see this =) it means: *his eyes fill up with bright red)
*He glares at you*
???: You shall perish
=)
*A knife appears in his hand*
*He teleports infront of you*
*He does a combo of hits that are so fast you can't even think about what's going on*
*He hits you with the final hit and you go flying away serveral meters*

Heather: *breathing hard and goes back into human form*

(btw when you see this =) it means: *his eyes fill up with bright red)
*He glares at you*
???: You shall perish
=)
*A knife appears in his hand*
*He teleports infront of you*
*He does a combo of hits that are so fast you can't even think about what's going on*
*He hits you with the final hit and you go flying away serveral meters*

Heather: "Woah..." *shakes her head* "Can't say I didn't deserve that..."

*he walks towards you slowly*
*His knife becomes bright red and around it there's a dark red aura*

Heather: "Anything for the others...I won't let them down again..." *they stand up and pull out a dagger of their own*
ah crap i keep forgetting their agender ahhh))

*he points his knife towards you*
*Suddenly a big red beam dashes towards you* *you have little time to react*

Heather: *ducks* "Listen. I did what I came for and I have to get back home. Maybe another time?"

???: I'll show you my DETERMINATION
*he strikes at you multiple times*

Heather: *sighs* "Well, this sucks." *goes into nightmare form and counterattacks. They get behind him and rakes their claws down his back*

*he kicks you away*
*He swings his blade*
*His eyes are filled with darkness*
*He switched to HATE*
*His blade is black*
*He strikes you*
*You slowly take damage*

Heather: *growls and goes straight for him, sinking their teeth deep into his left arm*

*he grabs you and slams you on the ground, prepares his knife and stabs you, a black beam comes out*
*The a shockwave pushes him away*
*Your power has been drained, you still have some*
*He dashes towards you, going through you, for a moment, nothing but then, the pain of 1000000 strikes hits you*
=)
*He turns around*
*His eyes fill with bright pink*
*He swings his blade*
*He switched to FEAR !*
*His blade became Pink*
(Pro tip, these type of attacks cannot be dodged, but you can try to make the effects slightly less powerful)
(Pro tip 2, you can deflect HATE attacks)
(Pro tip 3, you cannot deflect DETERMINATION attacks)

ok))
Heather: *flickering in and out of nightmare form* "Oh, you'll pay for that one."

*he strikes your arm*
*Suddenly you are scared*

Heather: "What...What are you?"

*he looks at you*
*He strikes your face*
???: YOUR WORST NIGHTMARE

Heather: *grabs his rist and swipes his leg* "Not a good answer. I'm still more afraid of the others than I could be of you."

*he recoves*
*He strikes you in the chest*
???: Well let's see these others you fear of!
*Everything goes black*
(Here you need to fill in the gaps, your oc has his fears, only you know them)

Heather: *flashback time* "I swear, I did everything I could! A-And only three got away! We did pretty good!"
???: "Pretty good, hm? Well, three still escaped. And YOU failed to stop them. Is this just some game to you?"
Heather: "YOU'RE THE ONE THAT TREATS IT LIKE A GAME! I JUST WANT TO GO HOME!"
???: *grabs Heather's arm and drives a blade into their side* "You know you can't go back. You're not human anymore, and you'd never survive out there. Even I wouldn't last long."
Heather: "You're insane...After everything you've done...You talk about us being monsters. But you...You killed your brother and lured people to your experiments. After all that, you have no right to say I'm not human."
???: *sighs* "Well, you failed. And I have no use for you now." *pulls out the knife and walks away*
Heather: "I-I swear, I can do better. Send me after them now! Those kids won't get away this time!"
???: "Fine, but don't come back until you've killed all of them."

???: Oh, i see
*He morphs into the guy in the flashback*
???: You failed, you failed everyone

Heather: "..."

Chris: heh

(btw when you see this =) it means: *his eyes fill up with bright red)
*He glares at you*
???: You shall perish
=)
*A knife appears in his hand*
*He teleports infront of you*
*He does a combo of hits that are so fast you can't even think about what's going on*
*He hits you with the final hit and you go flying away serveral meters*

Chris: ... ZEPAR! *suddenly a scythe appeared in his hand pure black* heh *stops himself and suddenly he's walking on air* let's do this

*his smile gets even more crooked the second that passes*
*He teleports behind you, but before you could react he teleports infront of you and kicks you right in the face*

Chris: heh ... witch hunter! *the scythe changes shape and I bring it down making a deep cut in his shoulder*

*he looks at you then at his shoulder, then back to you*
???: You shouldn't have done that
=)
*He dissapears, suddenly he dashes towards repeatedly, but he is so fast you can't catch him*
*When he does his last dash, your filled with small and big cuts everywhere*

Chris: ... ok zepar katana form... *suddenly the scythe becomes a katana * there *suddenly you can't even see him

=)
???: Do you think changing weapons will help? It will only make thing even more difficult, at least for you
*His knife becomes bright red and around it there's a dark red aura*
*You think that it's better not to get hit by the blade now*

Chris: wait I know this... OH SHIT

*his face becomes almost entirely crooked*
=)
???: *With a deep voice* Enjoy the bite of vengeance
*He teleports and dashes through you*
*At first no pain but then*
*You feel a stingy almost burning feeling*
*You look down and you covered in blood*
*You have holes all around your body, and they do not look small
???: Burns dosent it? The bite of vengeance..
*He dashes again through you, more holes appear*
*The pain becomes almost unbearable*
*His knife becomes black*

Chris: ... you...really...shouldn't....have done T H A T... *his eyes go pure black a red almost crimson aura surrounded him and white liquid covered his body but it hardens into a thick shell he now has horns and a weird mask as if it belongs to a demon*

*his blade becomes even more darker
=)
???: Hehe... people here always have two options, kill or spare, i will give you none
*His knife becomes totally black and it shifts to a Longsword

*growl*

*he looks straight into your eyes, it intimidates you, your slightly scared*
*His sword becomes red and he stabs the ground, around you, fire appears*
???: I am driven by many things, Determination, Hate, Fear, Vengeance, all of them make me keep going, i showed you my determination, I showed you my Vengeance, it's time to show you my FEAR
*Everything around shifts to black*
*You can see your best friend, leaving you alone and in the distance, disappearing, while his soul shatters*
*You see your family, abandoning you, and their souls shattering*
*You feel alone, scared*
*Everything around shifts to normal*
???: Oh, so you are afraid of being abandoned, *laughs* this means it will be easier then

Chris: ... infinite tsukuyomi... *looks deep into his eyes* EMATURASU *suddenly he lights on fire it's pure black the pain is more than anything he's felt* if you want a true fight I dare you to kill a God

*he raises his hand*
*You feel weakened and you fall on your knees*
???: I showed you FEAR, It's time to show you my HATE
*his blade turns black*
*He strikes the air*
*A black curve appears and starts flying towards you*

Chris: screw this.... *his voice becomes more high pitched and dangerous * ban....ki Kaosu buraddo mūn *his sword shatters*

*his eyes become black*
*His sword shifts back to a knife*
=)
*He dashes towards you and strikes you multiple times*

*blocks each one*

*he kicks you away*
*His eyes glow with bright white*
*He swings his blade*
*He switched to VENGEANCE !*

Chris: heh...

(forgot to say his blade turns white, and his eyes)
*He strikes at you*
*Bright light appears*

Chris: ... *a Cresent moon blocks the attack*

*he strikes multiple times, each one followed with a line of light*
*Only one of those strikes hits you*

Chris: ... *it doesn't cut through * heh

*he backs away*
*His eyes glows with bright red*
*He swings his blade*
*He switched to DETERMINATION !
*His blade became red*

Chris: ...

(pro tip, he can't be killed in this stage lol)
*He stabs the ground*
*Under you a colon of fire bursts out, making you fly into the air*
*He teleports to you and strikes you multiple times, then kicks you further into the air*
*Teleports behind you and prepares an attack*
*He strikes and you go flying to the ground, followed by a line of fire, making an explosion*