Kirei stares at Gilgamesh with a blank expression on his face, voice flat and disapproving. "It says not to tap the glass," he says, pointing to a sign that looks like it was written for children, before pushing Gilgamesh's hand down and away from the glass.
Gilgamesh laughs, and pulls his arm away. "Ha! The King of Heroes does not listen to messages written by foolish mongrels! I shall tap on the glass to my heart's content!" He continues laughing and tapping his index finger against the glass. Kirei sighs.
Why did he ever go out with him? Gilgamesh was the worst person to go out with (not like Kirei has anyone else to go out with, but he's completely content with that). This entire trip was a bothersome waste of time. It wasn't even close to the Hongzhou Feast Hall. What was the point.
The aquarium is busy, too, which is irritating. Crowds filter past, children yelling and squealing and slapping their hands against the glass. At least Gilgamesh isn't that foolish. Kirei bristles and steps to the side to let children run past - some stop and stare at him, as tall as he is. He pays them no more attention than necessary, just silently prays for the sound to stop. Or for something to happen. Something, anything interesting. Maybe an exploding gas line could turn this entire place into a storm of fire and screams. Maybe a sinkhole could open up and swallow the entire establishment into the earth. Maybe a sudden earthquake could cave in the ceiling and crush hundreds beneath the rubble.
He could hope, but nothing will happen unless he wishes it, and he'd rather save up his disasters for the End. Once him and Gilgamesh awoke Angra Mainyu and spilled out All the World's Evil onto the Earth. A second flood, Gilgamesh had said, to wash away the weak. Kirei cared not for any comparisons of the weak and the strong. Just as the weak writhe and beg and die, so do the strong. All will die in time, even Gilgamesh. And in that destruction, the survivors would find the true meaning of their lives.
Kirei could only hope he'd be there to witness that. How enrapturing it'd be, to see Gilgamesh's pretty face distorted in shock and outrage, as blood poured from his open wounds and his last breaths escaped his lips. One day, perhaps... He'd just have to fight to survive so that he could witness that and everything else.
Gilgamesh moves on from the tank, uninterested, and wanders to the next. The crowd parts as he approaches - his commanding presence drives them back and away, up against the tanks and the walls. Kirei follows him slowly, glancing at the tanks. All the fish looked the same to him - colors are all that really distinguished them, but the tanks just blurred into reflective water and ripples of color and motion. Kirei cared not for these things. Gilgamesh had wanted to go somewhere, since he was bored, because he's always bored and always wants to go somewhere stupid to do something stupid.
Fancy restaurants, amusement parks, crowded cafes, and now an aquarium. It's not like Kirei has anything else to do with his time, but it feels like a waste nonetheless. "Ah, an octopus!" Gilgamesh's voice breaks him from his thoughts, and he looks up to see him with his face pressed to the glass, staring at the shape of an octopus blending into its surroundings. "Truly a disgusting creature, even by the sea's standards." Gilgamesh looks at it anyways. "I had some, in my treasury, Kotomine. I had all of the most exotic animals, no matter how repulsive. Fish that coated themselves in wretched ooze, too. I doubt even this aquarium has those!" He laughs, and wanders off to the next tank.
"Ah, these fish are bright with all the colors of the world!" He watches them swim, scales shimmering. "As disgusting as the creatures of the sea are, they have the most amazing colors. Like the most expensive gemstones, Kotomine." He looks back at Kirei. "Look at them. They sparkle with the light of a thousand suns!" Kirei does as he's asked. The fish are nicely colored, yes, but Kirei finds no more beauty in them than he does anything else. They would grant him not even the slightest satisfaction if they bled. He has no interest in such things.
Gilgamesh doesn't care - his attention soon fades and he wanders to the next tank, and the next. He points out other fish and other sealife - nautiluses, squids, oysters, clams, sharks, everything and anything he sees. They all blend together in Kirei's eyes - the only thing that stands out at all is Gilgamesh, a beacon of gold in a sea of boredom and disinterest. And still, once that thought had wormed its way into Kirei's head, he can't stop running it through, again, and again - seeing him die, slowly, alone, abandoned, distraught and lost. Gilgamesh was always proud, always held his head high. Kirei wants to see him falter, for once in his life.
He wonders what he was like when Enkidu died, and wishes he could have seen that. Gilgamesh never once mentioned their name, and had only narrowed his eyes and crossed his arms when Kirei brought them up.
Enkidu would always be more important to Gilgamesh than he would, but it's not like Kirei cares. Gilgamesh isn't that important to him either. They were both just using each other, at the end of the day, to end the world, for differing reasons. Gilgamesh wants to rule again, over his ideal kingdom, and Kirei just wants to see everything fall apart.
For now, diversions like this would do. Kirei doesn't really care.