Beyond initial bleeding - extensive gastrointestinal issues, depending on where it hits. If it lacerates part of the intestine, it may leak feces into the abdominal cavity. It would require flushing and antibiotics to prevent going into sepsis from massive infection.

If it does enough damage, you could be looking at removing a portion of the intestines and possibly requiring a colostomy bag.

Abdominal wounds are no joke. The liver bleeds profusely if lacerated or punctured. All of the blood flow to the abdomen exits through the liver into the inferior vena cava.

1d6 in piercing damage but hit to the guts is probably a crit so 2d6. If you are lucky you will just be very injured. If you are unlucky you will go down and start doing death saving throws.

If you’re doing Star Wars cosplay, you’ll be totally fine. Unless you’re wearing the Qui-Gon Jinn costume, then you’re screwed.

Tldr it depends.

You might not notice with adrenaline pumping. As for lethality it really depends on where in your stomach you get hit and the care you get afterwards. In terms of the fight if it’s just your stomach area getting hit nothing shy of a spinal hit would instantly stop you. If they hit an artery you’ve got minutes. If they puncture your intestines and you can’t get care days, before infection catches up to you.

For the actual conflict the only things that will instantly stop are central nervous system hits (brain/spine). Heart and lungs are the next worst, but wouldn’t stop you from claiming a pyrrhic victory. Major arteries are the next big thing to worry about.

The worst part about getting hit in a non vital part of the chest wouldn’t be the force of the blow but the slow agonizing battle with infection that is not unlikely to follow. But absolutely livable and not nearly as bad with modern medical care.

Initially you would not much pain due to adrenaline. However after a moment, it would hurt so profoundly that it would command all your senses and drive you into a coiled fetal shape on the floor as you writhe in uncontrollable pain until either someone smashes your gut wound with so much immense pressure that it becomes difficult to breathe in order to keep you alive by reducing blood loss until you are taken to a hospital, or you quickly succumb to sepsis from your actual shit in your own intestines leaching into your blood slowly spreading the unending hoard of fecal bacteria towards your brain and you die painfully.

https://bookshop.org/p/books/body-trauma-a-writer-s-guide-to-wounds-and-injuries-david-w-page/10628914?ean=9781933016412

Book is written by a doctor for writers. Explains how a real world injury should be written in a story.

There’s a saying you want someone dead you shoot them in the head.

You want someone to suffer you shoot them in the gut.

It can be a slow miserable death as your body slowly goes into shock and dies. I’d imagine a blade would have a similar story.

There’s many critical structures to avoid such as a network of nerves sometimes referred to as angel pasta. There’s arteries and your gastrointestinal tract. Any of these being stabbed can game over or irrevocably alter the course of your life.

Your best bet is a stab that doesn’t go through your core but parallel like through the fat layer of your stomach.

Assuming it perforates the intestine - big infection from fecal matter getting into the abdominal cavity. It’s called peritonitis, and AFAIK it’s pretty much fatal if untreated. Severe abdominal pain as the infection spreads, all the vomiting and diarrhea cleans you out, and then the infection starts to shut your intestines and the rest of your organs fail while you go into sepsis and die. It’s not fast, either. It can take several days.

if stomach gets cut, the acid could flow out. Death by being dissolved by your own stomach acid wouldnt be nice one.

One of the shows I’ve been watching had this as its twist, part of a cliffhanger. There were hints before but you can’t not object to a short sword embedded in a guys belly having so little impact