I will post scans of the last two issues tomorrow if you want?
Agent X is actually [SPOILER - highlight to read]: An assassin called Nijo whose skills and personality was melded together with a telepathic terrorist and also from Deadpool himself.
Agent X and Deadpool have fought once in Cable and Deadpool #12. Deadpool won because he had slightly superior healing and so when they both shot each other down at the same time, Deadpool recovered first. But apart from healing I'd say they were pretty much even in everything. In fact Agent X may have slightly better fighting skills because he has Deadpool's skills, and Nijo's skills.............
No it is this random hero created just for the storyline. Agent X's job was to try and kill him. The problem was that this hero's power was to be able to not die. That caption is where Agent X tried to blow him up, unsuccessfully of course