Part 5: Game Mechanics - Item DropsGame Mechanics: Item Drops
Like most JRPGs, the Etrian Odyssey series employs a random drop system to determine what you get after finishing a battle. Item drops are purely used for selling or quests. They cannot be used for anything else. Enemies can have up to 3 drops. The 3rd drop is usually something called a conditional drop. You have to kill the enemy in a certain way or in a certain amount of time to get a chance to get the drop. Not all enemies have condtional drops, and some enemies just have 3 normal drops.
The way the game checks to see what you get is checking if you qualified for the conditional drop, and then checking to see if you got it, and then checks to see if you got the rare item and them the common item.
As for what's changed between games, the first game actually factored in the party's total luck in the drop rate formula. This is no longer the case. The only thing that can influence the drop rates is the Scavenge ability the Medic and the Hexer have access to. If you happened to get a conditional drop, the game wouldn't check to see if you got the other drops. Same with the rare drop. As mentioned before, that restriction is no longer in place. The drop rate for items are higher in this game. The lowest drop rate for an item is 10%, which isn't too frustrating to go for, but expect to spend some time looking for those items. You are limited to getting 8 drops from battles. Any more drops will be automatically left out of the results screen.
EO3 introduced an item called Formaldehyde which made getting random and condtional drops a lot easier. In order for the item to work, the enemies you wanted the drops from had to be killed on the same turn the Formaldehyde was used, but after the item was used so you had to time it right. If the Formaldehyde was successfully used, you would get all the dead enemies' drops, including the conditional drops even if you didn't qualify for the conditional drop. It's a pretty handy item, and has been in every EO game since then. EO3 also had the Lucky Hammer limit (that game's version of Force skills) which worked the same way, except you had to kill an enemy with it to get the drops. Sadly there was nothing like that in future games.