What do I do now? (KNY x Modern!Reader)

-Living Dead-

-(Genya's POV)-

I sat outside eating my breakfast. I had to get some fresh air after what happened earlier. '(y/n)'s going on a hashira mission? and on oyakata-sama's orders all hashiras are supposed to listen to her? '

"There are some things that I need to do. I'm sorry Genya, I can not really talk about it, it is something only I can know. Please forgive me."  

'What did she mean with that?'

I heard someone come up from behind and sit down beside me. It was (y/n).

"Are you really gonna go... Are you just gonna leave me here? What if something happens, you're not even a real demon slayer yet..." I said, poking my food around, not really feeling hungry.

"Don't worry, I'll be fine, and I expect you to work hard so you can beat me when I get back." She said with a wide smile.

"Promise?" I say, my voice exposing my worry.

"Promise." She says, giving me a hug. 'You better. I can't lose anyone else...'

We finish our meals just as Kanae and Shinobu comes out.

"Are you ready?" They asked her.

"Yes, let's go" She answered, standing up and walking with them. Not even looking at me. Not even saying goodbye. 'Please come back safe...'

As their forms disappeared I stood up, going to the Rongoku estate (Flame estate?) to continue the daily training, alone. I walk with my head low. 'God, why am I this worried? She'll be back. She'll be fine.' I try to reassure myself. 

"I expect you to work hard so you can beat me when I get back."

I remember her words. 'Yes, no need to worry. I just need to focus on getting stronger for now!' Feeling a little more at ease I ran the last bit.

"Ah, Genya-kun Good morning! Where is (y/n)-san?" Rengoku said loudly.

"Um, she went on a mission with Kanae-san and Shinobu-san." I said. He didn't say anything. Was he surprised about it? I knew it was a bad idea for her to go... "Rengoku-san, do you think she'll be alright?" I ask looking back down, not wanting to show my worried face.

"Of course! She's going with two amazing demon slayers by her side. There is no need to worry." He said reassuringly with his usual smile. 'Yeah. Kanae-san is a hashira and Shinobu-san has been her tsugoku for a long time. They're both great demon slayers.'

"Thank you Rengoku-san" I said feeling determined again. "Let's work hard!"

"Ha Ha, yes let's start!" He said and we started our daily stamina and speed training before continuing with reflex and movement training. 'It's way less fun without (y/n)' I think as I follow Rongoku's instructions. 'I wish (y/n) was here, it's always so much fun when she gets hit by the pebbles for being too slow to react' I think while practicing my reflexes with Tokito.

Time flew by and I ate my lunch and started sword practice with Iguro.

"Where's that annoying girl, why is she late?" Iguro says with a dark aura. I know something happened between them but neither want to talk about it...

"She's out on a mission Iguro-san!" I tell him.

"A WHAT! On who's order?!"

"Um, well hers? She left with Kanae-san and Shinobu-san" I say, a little unsure. Looking at Iguro, for just a second he looked worried? 'No She'll be fine, there's nothing to worry about.'