We'll Meet Again [Eruri] [COMPLETED]

[REINCARNATION AND TEACHER AU] ~We'll meet again. Don't know where, don't know when. But I know we'll meet again, some sunny day~ War. Levi could never live happily with Erwin. It was the nature of war. After the rumbling ended, Levi lived out the rest of his days quietly. Wishing to see Erwin again every day. When he...