Provided are an image forming apparatus and method, and an image forming system. A first obtaining unit obtains a print request including image forming data used for forming an image for each of logical pages. An output unit outputs a print medium on which an image is formed. A combining unit obtains, in response to the print request, from an external device that manages identifiers for specifying output numbers, information concerning a set of identifiers that specify the logical pages and an output number, and combines the obtained information with an image. A second obtaining unit obtains information concerning the identifiers combined with the image. A third obtaining unit obtains, if execution of the print request has stopped, print request stop information. A sending unit sends the obtained information concerning the identifiers and the print request stop information to the external device in association with each other.