1. A device controller connecting with multiple terminals and with at least one input-output device via a network, the device controller comprising: a reception controller configured to perform first authentication according to data input from a first terminal, which is one of the multiple terminals, and to cause the first terminal to obtain information on a specified series of processing based on a result of the first authentication; and an input-output controller configured to perform second authentication according to data input from a second terminal, which is one of the multiple terminals, and to cause a specific input-output device selected out of the at least one input-output device to perform the specified series of processing, based on a result of the second authentication, wherein the second authentication includes verification that a user as a subject of the second authentication is identical with a user as a subject of the first authentication, and the input-output controller allows the specific input-output device to perform the specified series of processing when the second terminal is selected in advance for the specific input-output device.