When reading, I met with a sentence with areka/あれか at the beginning and it's hard for me to understand. Much thanks if anyone can help me understand it correctly (in case I was wrong ).
Context : MC has been transported to another world and a girl saw him fall down from the sky. Then she brought him back to her house while he's still unconscious. After 1 week, MC woke up and the girl said he had slept for 1 entire week, and started to asking him a lot of questions since this is her 1st time to see a man fall down from the sky.
Girl「あれか。貴様は死人で、いわゆる幽霊とかいう奴か。 いや幽霊は触れないと聞くが、貴様はちゃんと触れるな。では違うか」 (my guess but not sure: "Oh I know. You're like a corpse when I found you, so you're like a ghost right ?")