Looking into the swirling void that was the portal inspired a lot of emotions within Karkat. Whenever he wasn't taking notes on random ghost stuff he noticed from Horuss or Muelin, doing homework, or some other shit, he was contemplating just what exactly he was looking at.
He couldn't help but wonder a lot about things when looking into it. Logically, it was one of the biggest scientific breakthroughs in the 21st century. It was an interdimensional portal that was stable, used up minimal amounts of electricity, and could be used to safely pass into it. Of course, not without proper equipment and determining if the environment was safe for humans.
There's also the fact it proved an afterlife existed. Admittedly, it was one more comparable to Limbo and it would most likely anger every existing religion, but that's beside the point. He had (ironically) living, breathing ghosts in front of him working on the portal, and even met some with concrete histories outside of the Ghost Zone! It would certainly catch someone's attention.
Those were the net positives about the portal. At least, those were the ones that Karkat could think up of. He actually was proud of Spades and really was happy his dad finally achieved his dream of proving ghosts were real after all these years. It almost made him want to stop trying to turn off the portal due to how heartbreaking it would be if he did.
But those positive feelings were overshadowed by… other emotions.
Philosophically? This portal was an absolute nightmare. Like he said before, his dad found an answer to the afterlife. And that's honestly fucking terrifying in some respects because that meant there might be a heaven and a hell of any religion. Does this imply that a god exists? Or multiples gods? Multiple pantheons that are divided, together, or simply exist on a single plane? This would personally set off a philosophical bomb in the world that nobody is prepared for. A sick part of him actually looked forward to it.
How would this also effect every other aspect of life? Would people even care about death if they knew there was a possibility of coming back? From what he could tell from his own research, becoming a ghost was a rare possibility. How many people would try, in some vain attempt at getting power, try to replicate it purposefully? How many would fail? How many would succeed?
Karkat couldn't help but imagine how many grieving family members, spouses, and others would want to jump in there at the chance of seeing a loved one again. He always started sweating whenever he saw Aradia look at it too long. He wondered if she saw this as her chance to see her mother again. If she wanted to just jump in and see where she could possibly be.
He never like it when she got to close to the portal. He personally made sure she never got to close to it or was alone with it for too long. Karkat knew she was over it for the most part, but it was a malignant thought that would stay in the back of his mind.
…Maybe he was being too negative about this, though. Karkat did figure his own experience with the thing would taint his views on it, if only a little.
Emotionally, he knew why he hated the portal. The thing had killed him. Ended his life before it ever truly began. While people did die younger, seventeen was still too young for someone to perish. Still so many things to do, people to see, and all of that.
And even if he was still here, he still died.
No matter what, ghost, halfa, or freak, that portal still killed Karkat Vantas.