Is there a pattern to how the vampire poet appears?
If you use summoning magic to escape from the main villain while he's summoning an army, the script won't activate a second time, and there won't be a battle.
In the end, my scenario ended right after being kicked by the titan.
Taking this opportunity, I'll make an announcement. Work on the patch, which no one was expecting anymore, has moved forward. I fixed about 15 bugs and implemented some requested features, added a couple of convenient features like buying all items or selling all resources with one click, etc. The work is still ongoing, but I think I'll release it in about a month.