Here's the completed save with all the H-Scenes in the gallery unlocked.
---
I killed the King, Sergeant, Marshall and Mayor because this was my own personal play through and I thought they deserved it.
The Sergeant has two unique scenes after completing his parts. It's the 1000 Gang Rape and the Fellatio scene. The 1000 Gang Rape will be viewable after you kill him (a replacement comes), however you'll need to go to the H Gallery to view his Fellatio as either the blonde haired version or the purple one.
The King, Marshall and Mayor do not have any unique scenes (outside story context), just unique lines.
---
If you're having trouble with the final boss, these magics are ESSENTIAL:
Crush Evil
Magic Reflection 2
To make the fight easier:
Cure 2 (If you fuck up)
Vigor (If you fuck up)
Heal 3
Mana Drain
Those 2 will keep you alive without having to use potions to recover.
Lastly, if you're not corrupted (theoretically, idk if you can not be corrupted), use your strongest weapon and its associated skill while refreshing your Crush Evil and Magic Reflection 2. Use Mana Drain when you start to run low on Mana and Heal 3 when you're dying - obvious stuff.
If you're a Slut Goddess, same thing, except use your scythe and use Ruin Sweep as Death Dance is too taxing on your Mana pool and does LESS DAMAGE in total.