I don't know what to name the article, so I'll just use this for now.
Five years after the war, 20-year-old Eren and 36-year-old Levi [there is an age adjustment here]
Levi has amnesia and can only remember things before he was 18 years old.
Eren started living together as Levi's guardian.
The story of Eren, a dad who has always had evil intentions towards Levi, and Levi, a 36-year-old rebellious young man who can only be regarded as having the mind of an 18-year-old, living together.
