Rance Quest:Equipment

Weapons and armor all have an overall rank that goes from nothing to ⑤. For shop items this rank raises after buying an item and leaving, so on your next visit that longsword will suddenly have a ① after its name if you bought one. This rank increases the price of items by 50% per level and damage/defense by 5% per level, meaning that at rank ⑤ items will be 25% better but cost 250% more gold. Additionally, this rank affects all random drops you get during quests. So if the shop is selling a rank ⑤ longsword, ALL longswords you get later will have rank ⑤ too.

Weapons, armor and some accessories dropped from quests can have a random number of bonuses, denoted by the number on the lower left corner of the item icon. This number can be increased by fulfilling the bonus condition(s) in the quest. Note that this method only affects items you get from the current quest. There are three types of bonus conditions, from top to bottom: collect a number of yellow spiky orbs, level up a number of times, win (not escape or time-out) a number of red spiky orb battles.

Unique Growth Equipment
While in your travels through Rance Quest, you may encounter special equipment(though the name does not change) that has a growth bar. Such weapons will increase in strength with constant use, up to a growth rating of 1000%. I have yet to confirm the actual growth, but one of my such weapon has a 50% attack boost upon hitting 1000% growth rate. Such items may become very handy, as it provides great power for its level.

The growth may have connection with exp the equiped character receives, not the number of times the item is used (confirmed, you just have to equip the item). My Onoha equiped a maid girl monster 1%. The maid only healed once. Onoha didn't get to move even once. After one dungeon, the maid was 80%. Growth is not working on characters that have too high level. For example, Rance lvl 51 is leveling on map with monsters level 43, and wearing a leather armor with level 39 requirement. It does not grow. After moving armor on Kanami who is level 40 (with a maximum of 40) it starts growing, although she does not get any experience due to hitting max level. Another example, Rance lvl 52, wearing a sword that is also level 52 and leveling on a map with monster level 43 - item does not grow too. So the rule seems to be that if you character is more than 5 levels higher than the map difficulty, then items he is wearing won't gain any growth.

For weapons, it seems that each 100% growth increases a weapon's attack by 10. I have yet to cross check all types of weapons to ensure this.

Armor of C or CC rank gets +5 to physical and magical defense for each 100% growth up to a maximum of +50, B or BB rank armor gets +10 up to a maximum of +100, and, finally, armor of A or AA rank gets +20 to both stats for each 100% growth up to a maximum of +200.

Accessories
Accessories will be destroyed when you unequip them. They usually give strait bonuses to stats and are useable by all character classes.

When a girl is "reset" due to the curse, the accessory will be "absorbed" by her in the process. The stats can be increased infinitely this way (in curse description it is said that there is a limit to how much each stat can be increased in this way). Also don't forget that each time you reset the girl, cost for her leveling increases, so it is better to reset her with the best accessory (rank A).