Rance IV:Secrets

Rare Items
Some non-essential items are rare drops inside Treasure Lumps around certain general areas. There's no tricks for getting them except grinding. The rewards are very good, however.
 * Research Core BF4 or BF5, Belief Key: Buster Sword
 * Defense Core multi floor, Betrayal Key: Hanny Knife
 * Buoyancy Staff F4 (also obtainable on 1F but may require being past Chapter 4), Chernen Powder: The item shop becomes Rance's. Everything costs no gold, and Yocchan becomes Rance's as well (new CG).

Mirror Fragments
Throughout the game, you can find Mirror Fragments. Bringing 4 fragments from the same mirror together saves the girl from the mirror, and you get a reward.
 * Set A, Rukira: 2000 gold
 * Set B, Ella: Lightweight Bow
 * Set C, Gezona: Lionet
 * Set D, Oichi: Strength Spray

150 Summons
If you summon Willis a staggering 150 times (summoning Johnny while in control of Maria does not count) she will offer you a prize of your choice:
 * 1000 GOLD.
 * Aa strip show (a unique CG featuring her and Mikan).
 * God Armor (c), the most powerful armor in the game at 45 DEF.

Mikan's Mechanics
For anyone who wants to spoil the surprise, Mikan's mechanics are as follows:
 * She will show up on a random chance of 1-in-5 if Rance has at least 3000 EXP (there is no way to "cheat" her by losing only a small amount of EXP).
 * Mikan's first few attempts are actually pre-scripted:
 * 1) She will screw up and set Rance's EXP to 0.
 * 2) She will enhance his weapon.
 * 3) She will screw up and set Rance's EXP to 0 again.
 * 4) Rance's EXP will triple.
 * All further attempts are genuinly random:
 * A 42/50 chance that she will 0 your EXP.
 * A 2/25 chance she will upgrade your weapon.
 * A 2/25 chance that she will triple your EXP.
 * In short, it is only worth using Mikan's services the first four times, if at all, minimizing your losses and maximizing your gains by save scumming. And yes: she will never get the ceremony correct the "normal" way.