Interesting. If not only Albus, but all his party members retain their memories, it is truly possible for them to go against the demon king before he got ahold of Fiona’s brother, or at least before the demon king assembled proper army.
Though that also means fighting as kids, the low level low stats gear-dependent (and item) build approach.
Anyway, I’m pleased with the twist and happy that the series continues (deservedly!).