Gaming device implementing a cooperative battle game in which the quantity of players of a group of players are managed based on mission success rates

1. A server device that is connected to a plurality of player terminals through a network to facilitate a cooperative battle game, the server device comprising:

a memory configured to store an initial upper limit of number of groups and an initial threshold value smaller than an upper limit of a group affiliation rate, wherein the group affiliation rate is a ratio of number of affiliated persons with respect to a quota of a group; and

a processor, configured to:

generate a plurality of groups;

at a start of the cooperative battle game, set, for the plurality of groups, the group affiliation rate to the initial threshold value based on the initial upper limit of the number of groups;

when there is a request for participation in a first group from the player terminal after the start of the cooperative battle game, distribute players using the player terminals to groups where the group affiliation rate has not reach the initial threshold value;

after the group affiliation rate of all groups has reached the initial threshold value, distribute the players using the player terminals to groups where the group affiliation rate has not reached the upper limit;

progress the cooperative battle game that gives missions set by the processor to each player belonging to each group in each of the plurality of groups, each of the missions set to each player indicative of one or more common enemy characters to be defeated by one or more player characters possessed by the each player belonging to the each group in the each of the plurality of groups;

calculate a mission success rate for all of the groups;

change the threshold value of the group affiliation rate from the initial threshold value to a second threshold value, based on the calculated mission success rate; and

generate a second group having the group affiliation rate set to the second threshold value.

2. The server device according to claim 1 , wherein the processor is configured to:

change the upper limit of the number of the groups from the initial upper limit after the group affiliation rate of all groups has reached the upper limit; and

generate a third group, based on the changed upper limit of the number of the groups,

wherein after the group affiliation rate of all groups has reached the upper limit, the processor is configured to distribute the players using the player terminals to the third group.

3. The server device according to claim 2 ,

wherein the memory stores an initial quota of the first group, and wherein the processor is configured to:

change the initial quota of the first group from the initial quota to a second quota, based on the calculated success rate; and

generate a fourth group having the second quota.

4. The server device according to claim 1 ,

wherein the processor is configured to change a difficulty level of the missions set by the processor, based on the calculated mission success rate.

5. A non-transitory computer-readable storage medium storing game program causing a server device, which is connected to a plurality of player terminals through a network to facilitate a cooperative bathe game, to execute:

storing an initial upper limit of number of groups and an initial threshold value smaller than an upper limit of a group affiliation rate, wherein the group affiliation rate is a ratio of number of affiliated persons with respect to a quota of a group;

generating a plurality of groups;

at a start of the cooperative battle game, set, for the plurality of groups, the group affiliation rate to the initial threshold value based on the initial upper limit of the number of groups;

when there is a request or participation in a group from the player terminal after the start of the cooperative battle game, distributing players using the player terminals to groups where the group affiliation rate has not reach the initial threshold value;

after the group affiliation rate of all groups has reached the initial threshold value, distributing players using the player terminals to groups where the group affiliation rate has not reached the upper limit;

progressing the cooperative bathe game that gives Missions set to each player belonging to each group in each of the plurality of groups, each of the missions set to each player indicative of one or more common enemy characters to be defeated by one or more player characters possessed by the each player belonging to the each group in the each of the plurality of groups;

calculating a mission success rate for all of the groups;

changing the threshold value of the group affiliation, rate from the initial threshold value, based on the calculated mission success rate; and

generating a new group having the group affiliation rate set to the changed threshold value.