The Longest RP Ever Submitted is a matter of contention among roboteers, as several posters are notorious for making excessively long RPs for many of their fights. Succotash_54 is considered by many to have the long-standing record for the longest RP, at roughly 1600 words.
Terminus vs Influenza
Terminus vs Influenza Is a potential candidate for the longest RP, clocking in at 1788 words. The length of the RP is the result of Prince Palatine (the driver of Terminus) and a few other posters referring to Influenza as "Clown Breath" on Skype. After Spatula threatened to add a paragraph to the RP every time the others said "Clown Breath", everyone on Skype immediately began saying "Clown Breath" repeatedly, hundreds of times.
Aware that his bluff had been called, Spatula resolved to follow through and write an excessively long and droning RP to fulfull his threat, most of which has nothing to do with the actual fight. It consists of a science fiction story (part of a series he intended to write anyway called 'Atna'), plus some tactics for the fight worked into the plot at the end. The RP went on to successfully win the fight for Influenza, making it also the longest RP to actually work and not backfire.
Kraze vs Jupiter 2 V
Kraze vs Jupiter 2 V can also be considered for the longest RP, at a total of exactly 4,000 words, over twice that of Terminus vs Influenza. The RP consists of a short story where Kraze returns to the team base following elimination from playoff contention in Ruination: The Omen, fearing punishment for failing to progress. A number of factors combined to result in this almost pointlessly long RP: this was the final week of the season, the aforementioned elimination from contention, and the owner of Jupiter 2V had not been seen since the tournament began. However, the RP had no real strategy within it, and the match ended up in a forfeit victory for Kraze, unlike the Terminus vs Influenza match.
NFX, the owner of Kraze for this match, has done similar things in the past, submitting irrelevant or less than serious RPs when he faces an absent opponent in the final week of the tournament, and he has been eliminated from playoff contention. This happened both when Frequency faced Tartatus in the previous Ruination (which was itself referenced in the Kraze vs Jupiter 2V fight), and SWARM faced Golden Destiny 2 in League of Robotic Excellence. However, neither of those RP's were anywhere near the length of Kraze vs Jupiter 2 V.