^It wasnt a shit ending- its a forced sudden ending. And I think it was a pretty good way to wrap it up- and nobdy could have done much better. Series getting cancelled with little warning for the author is a reality of manga series you just have to live with.
The only way to avoid it is only start a series that you know already finished and you know wasnt cancelled early.
Tell that to Matsumoto Tomoki, the poor guy had planned a 7 volume vampire story with everything planned with twists, story, flashback and hig quality drawn lesbian vampire then the editor came and say "The 3rd volume will be the last".
I'm still sorry for him so much (and for us)
Seifuku vampire was a fucking great manga, but damn he did a really goodd job wrapping it up within the limited space he had
Shot himself in the foot when he included a male char to live with our MC in a yuri story tho, Im 90% sure had he made the vampire who bit our MC some cute loli girl instead it would still be running till today