Where do I get the manuals for other metals?
I don't remember which one is where:
— Second mine (north of the first, next to the abandoned city). Need to beat the boss that has 30 HP but weakens your attacks 1000 times or so. Probably easy if you can handle the mobs and have enough buffs from the crests.
— Orc forest. You can avoid all the orcs, but from what I read here you need Lv 100 (and/or some point in the game) to enter. Being catched without the right way to escape will lock the recruitment of the blue girl.
— Slime cave. Need to beat three slimes guarding the entrance, find the key, and then conquer the kraken which drops the manual.
— Manual for silver is at Narika's headquarters in the destroyed city (the HQ is guarded by her thug), or alternatively can be bought at 5th city for 1M gold.
— Manual “匠” for three best ores (demonite, magnetite, and cobalt) lies in the deepest part of the tentacle forest. To enter, you need to destroy the blue tentacle wall by inflicting 80M damage in single turn. Extremely profitable, one looting of the area with these easily yields several millions of gold.
Remelting ores doesn't give THAT much more money than selling them raw, but crafted equipment is useful to conquer next-tier areas.