"River"
Capricorne

Luigi knelt down on the ground, panting for breath and trying to hold back the vomit that was brewing in his throat. The blue Goomba had surprised him, coming from the right, seemingly out of nowhere. He hadn't had time to think, he hadn't...

How does Mario do it? Luigi thought. How can he handle it? How can he take this... mayhem? This destruction? This carnage?

The younger brother rested his back against a blue brick wall of the underground, a haunting melody echoing from some unseen orchestra. Luigi was consumed by his thoughts, and his grief. But he couldn't rest. He mustn't. The Princess was gone. They had to get her back, no matter the cost.

But this...

Luigi did not see the glory. He did not find joy in what he and his brother were doing. He found no comfort in climbing the inexplicabley place staircase. There was no solace in the flag raising. The fireworks did nothing to quell his pain. And the pipes staring at him, hungering for him, the pipes that waited, open like the gaping jaws of the Koopa King himself... they only filled Luigi with dread.

But Luigi knew he must persist. He must enter the underground. Mario told him of a hidden cavern, one that his brother went ahead to find. A cavern that was filled with more pipes. Pipes that would allow the two brothers to warp closer to King Koopa's castle, where the fair maiden was being held. So he entered the pipe and then...

The Goomba had surprised Luigi, but at an inopportune time. He had just acquired a fire flower. Luigi had heard of the mythical plant before, but this was the first time he'd ever actually seen one. All the legends were true. When Luigi picked the flower from the block it was growing out of, he felt his body fused with energy. Heat surged through him and he felt stronger, more powerful. And then he saw the Goomba.

It was pure instinct. Luigi's hand shot out and a ball of green fire erupted. His entire hand was ablaze, but not for long. Soon the flames had form into a ball that launched itself across the ground, bouncing over bricks, before it found its target.

The Goomba made no noise. Luigi wasn't even sure if Goombas were capable of making a noise. This one would be making no more, if it ever made any. But the Goomba did burn, it did that quite well. It burned and scorched, and the cavern was left with the smell of rotting fungus. And that was all. There was no body. There was no trace that this creature, like so many more that Luigi had killed, this creature that was simply following orders, had ever existed.

Except for one thing.

One tiny, miniscule, trace. Something you wouldn't even notice walking by.

Blood.

A small splat, a few drops of blood.

Luigi fell over, unable to hold back the vomit or the tears any longer. He wasn't made for this. He wasn't meant for it. He couldn't handle it. With ever creature he killed, he died a little more on the inside.

But he must persist. He must pursue. He had to find a way to deal with it. The Princess must be saved.

And, after all, it was only Level 2.