Method for providing battle royale game capable of allowing items to be upgraded and server using the same

A server for providing a battle royale game which upgrades items, comprising:

• at least one memory that stores instructions;
• and
• at least one processor configured to execute the instructions to perform or support another device to perform processes of:
• (I) on condition that (i) information on each of a 1-st main item to an n-th main item, (ii) information on at least one 1-st sub item corresponding to the 1-st main item to at least one n-th sub item corresponding to the n-th main item, wherein each of the 1-st sub item to the n-th sub item be consumed respectively for upgrading each of the 1-st main item to the n-th main item includes at least part of each of a (1_1) -st sub item to an (n_1)-st sub item directly consumed respectively for upgrading each of the 1-st main item to the n-th main item and each of a (1_2)-nd sub item to an (n_2)-nd sub item indirectly consumed respectively for upgrading the 1-st main item to the n-th main item, and (iii) 1-st hierarchy information to n-th hierarchy information, wherein each of the 1-st hierarchy information to the n-th hierarchy information includes each of information on hierarchy among levels of the 1-st main item to information on hierarchy among levels of the n-th main item, each of information on hierarchy among levels of the 1-st sub item to information on hierarchy among levels of the n-th sub item, and each of information on hierarchy between each of the levels of the 1-st main item and each of the levels of the 1-st sub item to information on hierarchy between each of the levels of the n-th main item and each of the levels of the n-th sub item, have been stored and managed in a database, acquiring at least part of a k-th main upgrade request for upgrading a k-th main item and a k-th sub upgrade request for upgrading a k-th sub item from a specific user terminal corresponding to a specific player among a plurality of players participating in the battle royale game, wherein the k is any one integer among 1 to n;
• and (II) performing at least part of (i) a main upgrade process which upgrades the k-th main item and provides an upgraded status of the k-th main item to the specific player, in response to determining that a (k_1) -st condition for upgrading the k-th main item is satisfied by referring to information on one or more specific possessed items of the specific player, information on the k-th main item, information on the k-th sub item and k-th hierarchy information, wherein the k-th hierarchy information is information on hierarchy among levels of the k-th main item, information on hierarchy among levels of the k-th sub item, and information on hierarchy between each of the levels of the k-th main item and each of the levels of the k-th sub item, and (ii) a sub upgrade process which upgrades the k-th sub item and provides an upgraded status of the k-th sub item to the specific player, in response to determining that a (k_2) -nd condition for upgrading the k-th sub item is satisfied by referring to the information on the specific possessed items of the specific player, the information on the k-th sub item and the k-th hierarchy information.