Nearly every mental change is needed sooner or later (main exception are the machines that let you mess with fetishes and sensitivities). So every one of those books is going to be trashed and replaced. I do the interest books first, but it's no big deal. As a heads-up, the second set of mental rooms has the same thing to a much stronger degree. Read every non-lewd book you can before you start pumping knowledge, because once you're done it becomes almost impossible.
No, it's a literal ingame scam. I shouldn't have said "every book". There are some that you might decide to skip if you don't need their effect, like the one that buffs a specific Earth spell.
There is a minor sidequest that has alternative text/solution if you've actually read the book.
Go to the slime summoner in the refugee camp without your slime summoned. Once you get to Nephlune, there's a trainer in the Adventurer Guild who can teach wind and thunder forms. There may also be further training in the academy in Verdeaux, but I don't think it's been implemented yet.
One of the best things to feed the slime is the Maleficum, because the Slime does not get the corruption that comes along with using that material.
What about the consideration of giving aura a material enhancement or feeding it to the slime? What's more important?
Well, I used to reserve all the best stuff for myself and feed everything else to the Slime, but this was on a save before the 2nd "nerf" increasing the summoning cost by 2 instead of just 1.
On Normal, there's merit to that plan. On Hard, you pay out the ass for enhancements to Aura. My thinking is, if you have to take on a boss that the slime has no counter for (e.g. ones that use Darkness attacks), and that makes the fight very hard/impossible (which is rarely the case) there's always Star Knightess. And those Darkness bosses can be Blessed Bomb+'d to oblivion.
Don't remember the exact level they got those skills at, but the easiest way to do the new underwater stuff is to have the Air form Slime with the bubble ability, certainly.
The Slime can become an absolute beast if you feed it enough. Even with the MP cost nerf it's usually worth doing.
The idea is that the corruption is mostly-linear to 1.0, but with the possibility of adding more paths/deviations in later versions.
As Pretentious Goblin said, the goal from now to 1.0 is adding depth; having a game you can play from start to finish with two defined endings (beating the Demon King, and being fully corrupted). Once that is done, we can work on width, giving more options for how paths progress and what options the player has.
Kids these days have been ruined by all the Open-World games that always promise "freedom to choose".
I would love, at some point, to make a game where you truly have enormous levels of control over the development of the world and the story that happens within it, but I'd need an absolute metric buttload of dev time and money to pull it off.
