This is a function of the game where you can delve into an item to level it up. In each item there is a number of levels that are randomly generated by the game for you to go through. For common items there are 30 levels, rare has 60, and legendary items have 100 levels to grind through. In each level there are a randomly made set of enemies that are a certain level depending on the type and level of the item as long with an special space where if you go onto it you skip the level and dont have to fight the monsters. And with every ten levels there is a boss you are given the option to defeat. There are different require ments that can be met to gain acces to fight a certain boss that will net you better rewards than others, such as if you go through all 100 levels of a legendary item without leaving you can fight an item god 2 which is the highest rewarding boss of the item world. Another thing that is inside of items are creatures called specialists. These creatures add stats to the item depending of the type of specialist it is. What you can do though, is you can go into the item world, find the specialist and defeat them to "subdue" them and then you gain the ability to move them from item to item and combine them with other specialists of the same type. One thing you remember in the item world is to carry a Mr. Gency's Exit with you. If you the enemies in the item world ever become too tough and you die, you have to restart from your last manual save. Although there are two ways of getting out of the item world. After every boss level you have the option to exit the item, and the other option is to use a Mr. Gency's exit to exit wherever.