My New Isekai!

"Haru! Haru," my mother called out to me from downstairs.

"Coming…" I said with a tired sigh.

I reached downstairs and noticed something...weird…? Instead of seeing my mom, I saw a dark entity staring at me with hideous crimson-red eyes.

I stepped my foot back, having it shake like a mad-man. "W-w-who are you?!"

The dark entity looked at me with an even more intense, heart-piercing grin. "Ah… Haru, finally."

My whole body was shaking. "What did you do to my mom?!?!" I yelled out in absolute fear.

"Your mom," the thing questioned. "Ohhhh, that old hag? I took care of her already," it said with an evil grin.

My right eye twitched. "... what…?"

"I killed your mom. What are you going to do Haru?"

"What am I going to do?" I said getting up on my legs, and clenching my fist as hard as I can. "I am going to beat you to a bloody effing pulp!!"

I ran towards the entity and sent my fist flying right towards them. But… my fist went right through them…?

I stumbled back. "... what just happened?"

"Why the pause? Can't you tell? It's me, Zim."

"Zim…? Who—"

I got cut off by Zim teleporting up to me and grabbing my head. "Have fun," he said with a grin.

I screamed in agony. This hurt more than anything that I've ever experienced!

Two reddish-black horns came from the top of my head. Making it seem as if I turned into a demon.

"Ah, yes!" Zim said, "I'm glad you chose me, master!!"

"Master?" I said in a deep, groveled voice. "I am not your master! Leave me alone for God's sake!" I yelled, sending my hand flailing in Zim's direction, causing a massive wave of energy to fly out, cutting Zim in half.

"Yay, you've fully unlocked your full power!" Zim stated, "Since you're already like this… cause some destruction."

I yelled out a loud roar, causing an earthquake. "The world is mine!!"

I woke up in my bed, holding my heart as it pumped fast. Faster than it ever has before.