Deku's Dragon Maid

Killer vs Demon

Izuku sleeps soundly on his bed until something wakes him up.

"WAKE UP KID!" Grim shouts while also banging two pans together

In a panic Izuku falls out of his bed and onto the floor. "Ww-what's happening?" Izuku asks panicked

"Bitch it's time to train. Get your broccoli looken ass ready." Grim says with a smirk

"But it's four in the morning." Izuku says rubbing his eyes due to his drowsiness

"Don't care. Now you have 5 minutes to get dressed and eat or else you're doing 5 million one finger push ups. Also time started 1 minute ago,  better get going." Grim then walks away as Izuku rushes to get ready 

(Time skip  minutes and thirty seconds)

Izuku runs into the main room out of breath of breath to see Grim sitting on the couch talking on the phone.

"Yeah your squeal was amazing, loved the end credit scene. Made me laugh my ass off." Grim says before noticing Izuku. "I gotta go the MC just showed up." Grim says "Of course we're still doing poker next week. Ok see ya." Grim then hangs up the phone.

"Well looks like you made it. Now lets get to training." Grim say as he stands up. "Alright you get the first attack. Also if you don't start using your demon magic I'm gonna hit you twice as hard." Grim tells the bush hair hero.

Izuku looks at Grim and sees tat he places his hands in pockets and calmly waits for his attack

(Izuku pov)

Grim just stands there and waits for it. I breath out and focus on the magic I can feel. Due to the seal Grim placed on me I can't use or even feel my dragon magic so the magic I am feeling has to be my demon magic. So I focus on drawling it out like how I would normally draw out my dragon magic. I try but nothing happens.

"Nice try but that's not how it works kid." Grim says out of no where

"What do you mean. This is how I used my dragon magic?" I ask

"Boy, comparing demon magic to dragon magic is like comparing the Justice league movie to Infinity Wars. There's a big difference." Grim says with a smirk

"Then how do I use it?" I asks

"Unlike dragon magic that is drawn out naturally by a dragon, demon magic relies on emotions. Primarily negative emotions such as anger and the fear of others." Grim says while walking toward Izuku.

"The look in your eyes tells me you've never been all that angry before, have you?" Grim says while staring into my eyes

"I've always been able to keep my anger under control." I replie

"That's no good?" Grim says with a sigh.

"Why's that? When my uncle was teaching to use demon magic he wasn't in the slightest bit anger." I explain

"Demon are always angry and we make that anger a part of use. We merge it with our very being it's a part of us. That's why we can use our magic to it's fullest potential without having to actually being angry all the time." Grim explains

"So I have to get angry?" I question

"Not just that. You need to embrace it, make it a part of you. Only then can you truly unlock the full potential of your demon magic.... or when ever the plot decides it's time." Grim shrugs

"At this point I've stopped trying to understand you." I tell him with a sigh

"That's probably for the best. Now lets get you angry" Grim says with a smirk on his face. "Now I want you imagine Tohru getting badly injured. Better yet me show you." Grim says as he places his hand on my forehead.