Neither of them had actually thought about it before. Never really believed it could happen anyhow.
Levi was convinced he was too fucking old anyway. Too jaded. How could he ever be worthy of Eren?
Eren was convinced he was too young. Too dangerous. How could he ever be worthy of Humanity's Strongest?
Then again…maybe it had been clear where things would lead to from the very start. And one sunny afternoon Levi had looked at Eren just a second too long and suddenly their worries didn't matter anymore.
Eren was so beautiful. Even the sun couldn't keep up with him.
Levi was…well…simply Levi. Eren didn't see anyone else.
When Eren awoke on the next day his first thoughts were filled with light. Instantly his heart skipped a beat and when he stood up to go into the bathroom he felt like he was floating. The world was still the same to his surprise. Yet it felt so different.
After washing and scrubbing himself twice all over he shuffled into the kitchen and without really considering it first, he fetched two bowls of porridge and hasted off to see Levi.
Levi didn't tease him for forgetting the spoons. In the end they didn't eat anyway. At least not for a while.
It had to remain a secret, of course. The possibility for the authorities to doubt Levi's loyalty when they'd find out was too risky. It wouldn't matter to them that Eren relied on Levi just as well to keep him from harming others.
So they tried their best to be discreet.
Sometimes during training Levi's hand would linger barely noticeably on Eren or squeeze shortly.
Sometimes during eating Eren's feet would nudge against Levi's with a muttered excuse or elbows would touch.
When they met in the hallway knuckles would incidentally brush against each other and peeks went back and forth. Fleeting smirks and stealthy gestures, received with increasing heart rates and faint blushes.
Messages were written and exchanged. Read in deserted corridors, quiet corners under stairs, or in the stables, raising soundless beams. No one ever wondered about notes changing owners. Everybody knew that Eren couldn't read or write and that Levi was helping him. They didn't have to know that Eren had made quite a progress.
You honestly got me soap for our one week anniversary…
Tonight right before curfew. Same place.
Did you know your Titan has your eyes? Only bigger. Fucking gorgeous.
Eren hid every single piece of paper between his fresh clothes after running his fingertips over Levi's neatly written words. The latest one he usually kept under his pillow.
Happy weekiversary.
Thank you for last night. I like your nose. Boop! (Do you write boop! like that?)
Dreaming about you too.
Levi had them all collected in his secret drawer, shaking his head at himself for his youthfulness and smiling softly at Eren's bold handwriting that got better with every word.
Even Hanji didn't know about that drawer.
They met late at night for gentle whispers and stormy kisses.
Levi would never admit how Eren's ravenous passion drove him crazy. Nor would he ever admit how much he loved how Eren's eyes would shine afterwards. And how safe he felt with him.
Eren showed Levi over and over again how weak he was to his coy tendernesses. He couldn't get enough of Levi's lips, or of his deep voice that kept on telling him all kinds of sweet things. When Eren would sneak back into his room even later at night, his cheeks were swollen with elation, his whole being radiating it.
Levi scheduled joint patrolling hours and private lessons.
Mikasa and Armin exchanged knowing glances. Eren didn't notice.
Levi's frown was a little less deep these days. Erwin didn't comment on it, deciding that if he didn't know for sure, he didn't have to report anything. Hanji on the other hand got curious and started to casually drop information, like mentioning an upcoming meteor shower one week during an experiment with Eren.
What about star gazing tonight?
I fucking love stars.
Levi opened a small bottle of sweet wine that night. They drank it out of teacups as they marvelled at the sky and the fireflies nearby.
When Eren kissed Levi, he tasted like wine, confessions, and moonlight.
Hanji nodded knowingly at Levi's expressly neutral behaviour the next morning. Jean looked at Eren's dreaminess and only rolled his eyes. Under the table a hand shortly squeezed a knee before coming up and reaching for freshly steeped tea.
Their nighttime visits continued.
Levi told Eren of the underground city while Eren held him close and caressed his back.
Eren told Levi about growing up in Shingashina and remembering naps in flower fields while Levi washed his hair in the tub.
A few days later a soldier wondered about a single wild flower shyly peeking out of Eren's jacket pocket.
Thank you for the daisies. They are beautiful.
They are called daisies? Sounds nice.
The rumour spread that one morning Captain Levi had been caught smiling into his tea at breakfast. Nobody dared to ask why or if it even was true. It couldn't be.
Still, people began to observe more closely.
Eren would visibly lighten up when Levi was mentioned or stood nearby. It wasn't something new to anyone. Eren had never made a secret about his obsessive infatuation.
Levi got spotted a few times to visit Eren in his room. It wasn't too suspicious—he had every right to do so after all—and who would have seriously thought that Levi would let Eren doze off in his arms, while he petted his head.
You look cute when you sleep.
Sorry for drooling on your shirt.
Months passed by.
Levi started to teach Eren how to play chess.
Eren showed Levi how to enjoy the winter times.
Why don't you just tell me why I need to bring a carrot tonight?
You'll see.
Eren was a source of warmth in the freezing snow. Especially when he laughed.
Levi was…well…still simply Levi. And when he looked at Eren with affectionate eyes, his nose and cheeks red from the cold, all Eren wanted to do was catch the moment.
On the next day nobody mentioned the scowling snowman with the stone buttons, face mask and broom a couple of meters away from the headquarter, surrounded by one small and one bigger set of footprints.
The next evening Levi joined the young adults during their vespertine matches of Whist for the first time, ordering Eren to explain the rules to him. If anyone remembered the Captain's former—and repetitive—mentions of his dislike in card games, it wasn't brought up.
Life went on. They undertook an expedition and somehow succeeded. That night Eren snuck into Levi's room and together they forgot the world. Afterwards Eren hummed Levi a song his mother had sung to him and Mikasa when they'd been little. It was the first night they completely spent in each others company. Levi had never slept this well before.
Spring came and Eren seemed to glow.
Summer came and Levi invented plausible explanations for the vase with roses that appeared on his office desk one day. People swore he smiled at them from time to time.
Neither Levi nor Eren would notice how the other soldiers had began to make sure they'd end up sitting close to each other during their meals at least once a day, leaving two adjacent, diagonal, or facing chairs unoccupied. At least they didn't for a long time.
Yes, they all knew.
None ever said a word.