A. Have the author create a "proper" sequel
B. Alter the story to prevent it from going astray
C. Prevent the series from ending too early

A -- honestly, most manga i've finished don't really need a sequel. nine times out of ten they end up overstaying their welcome as opposed to leaving me wanting more. there are a few animes i'd like sequels for though: 12 Kingdoms, Baccano, Cowboy Bebop

B -- (1) Berserk - alter it at the tone shift (2) Full Metal Panic Sigma - alter it at the point where every character became a shell of their former selves (3) Shamo - where the soft reboot kicked in

C -- Negative Happy Chainsaw Edge, Cat Street, Banya, Blue Heaven Beelzebub

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