This was the first No Mercy event to take place in the WTX Universe. It took place a full month after September's Night of Champions. It will be followed in November by Survivor Series. It is also considered the Season 3 finale.
Nine professional wrestling matches took place at the event. Following the events of Night of Champions, in which Triple H retained his World Heavyweight Championship inside Hell in a Cell against Wade Barrett, and Seth Rollins defeated former Shield partners Roman Reigns & Dean Ambrose to become #1 contender, the two faced off in the first confirmed main event for the PPV. This will mark Seth Rollins' second ever opportunity at a world championship as well as his first ever one-on-one opportunity. At the Night of Champions event Rollins won in questionable fashion, stealing the pin from Dean Ambrose (who had just hit his Dirty Deeds finisher on Roman Reigns) by throwing Ambrose out of the ring and covering Reigns. Due to this on the following episode of Raw Ambrose got a rematch with Rollins with added speculation that Ambrose would be added to the World Championship match were he to win, this was not the case however as Rollins proved he earned the shot defeating Dean Ambrose.
The second confirmed match was for the vacant NXT Championship. At Night of Champions NXT Champion Corey Graves retained against challenger Batista, he however suffered severe injuries in this match as a lot of it consisted of him taking offence from the challenger. The following episode of NXT saw Graves vacate his NXT Championship with the new champion set to be determined via a 16-Man Tournament that would take place over the next several weeks of NXT with the final two contestants facing off for the vacant championship at No Mercy. The opening rounds saw Adrian Neville defeat Big E, Kofi Kingston defeat Justin Gabriel as well as a returning Drew McIntyre defeating Tyson Kidd. The following week saw Suicide eliminated by AJ Styles, Batista defeat Mark Henry as well as Bray Wyatt eliminating Bobby Roode. In the final qualifying rounds, Austin Aries eliminated Sheamus and Yoshi Tatsu eliminated Sami Zayn. The quarter finals then saw Kofi eliminate Neville, Styles eliminated McIntyre, Wyatt eliminate Batista and Aries eliminate Tatsu. This brought the semi-finals to Kofi Kingston vs. AJ Styles and Bray Wyatt vs. Austin Aries. On the final NXT before No Mercy, Austin Aries was determined as the first finalist after defeating Bray Wyatt, to close the show Kofi Kignston got the upset victory over AJ Styles, setting Austin Aries vs. Kofi Kingston for the vacant NXT Championship at the event.
The third match determined came to be following the back and forth competition between The Dudley Boyz & 3MB. A few months prior to the event The Dudley Boyz won the WWE Tag Team Championship from Vitamin C, the primary reason being that Christian & Chris Jericho were becoming a disfunctional tag team. Following The Dudley Boyz championship victory they began to be pursued by upcoming tag team 3MB, which had switched out former member Jinder Mahal for debuting member Wolfe. Heath Slater & Tyler Reks had picked up a victory over The Dudley Boyz entitling them to a Tag Team Championship opportunity, the following week on SmackDown the shot was given to the debuting Wolfe and fellow 3MB powerhouse Tyler Reks. Reks & Wolfe won the tag championships and held them for three weeks before losing them back to The Dudley Boyz in an Elimination Tornado Table Match. The Dudleyz were not finished with 3MB there as Heath Slater stated that he wanted a shot now at the Dudleyz alongside a 3MB member chosen by the audience. On the September 26th edition of SmackDown it was determined to be Slater & Wolfe who would challenge The Dudley Boyz for the WWE Tag Team Championships at No Mercy with an added stipulation that the losing team would be forced to disband.
The fourth match was determined over the past two weeks on Raw. Following Leo Kruger's Intercontinental Championship win at Night of Champions he immediately set an open challenge to defend the belt which was accepted by five challengers, Randy Orton, Tyler Breeze, Roman Reigns, Damien Sandow and the winner of the match, Titus O'Neil. The match came down to O'Neil and Breeze and following O'Neil's victory Breeze raised the arm of O'Neil. Due to this O'Neil gave him a singles non-title rematch the next week which Breeze won, setting up an Intercontinental Championship match for No Mercy.
The fifth match and final main event match was set on the October 3rd episode of SmackDown, following Goldust's historic WWE Championship win over The Miz the following week Goldust was informed he would be defending the championship, just five days into his reign. There was speculation that his challenger would be The Miz, invoking his rematch clause, this was not the case however as the entire feud between Goldust & Miz was revealed to be a setup by Paul Heyman with whoever came out of the feud with the championship being forced to face Paul Heyman's chosen challenger and his own client, Brock Lesnar. Lesnar dominated Goldust throughout the match and won with a single F5, claiming his first WWE Championship and second World Championship in the series' history. This was revealed to be a part of Heyman's plan to rule SmackDown with an iron fist, picking those who he deemed as worthy to challenge for and earn the championships, generally with his chosen challengers not struggling at all to claim the gold. Heyman backed up this group he has been creating by stating that "they are just ordinary superstars that (he) feels are worthy of championship contention, it is the champions duties to defend their championships over any obstacles thrown their way. None of (his) chosen challengers challenged the former champions when they were weak so there really are no excuses. It just goes to show that who (he) is chosing truly deserves it more." Following Lesnar's win over Goldust, he was challenged by The Miz who was frustrated at the lack of respect he had as a former WWE Champion (not being given his rematch), Heyman stated that Lesnar is a defending champion and accepts The Miz's request. Before the match could begin Goldust charged to the ring, grabbed a steel chair and laid out both men, hitting one after the other. Heyman then announced that his client Brock Lesnar is becoming sick of both men and will destroy both at No Mercy. Setting the final No Mercy main event as Brock Lesnar vs. Goldust vs. The Miz with the WWE Championship at stake.
Also set on that episode of SmackDown was a rematch between Paige & Kaitlyn for the Women's Championship. Kaitlyn, who had been defeated with barely any offense in her initial shot at Night of Champions, insisted she slipped up and deserved another chance, Paige being the defending champion accepted her requests and gave her the shot at No Mercy, changing things up this time and making their match a TLC Match for the Women's Championship.
At the October 8th episode of NXT a Cruiserweight Championship match took place between new champion Curt Hawkins and former tag team partner and champion, Zack Ryder (who had invoked his rematch clause.) As the match took place Hawkins was unable to defeat Ryder with his finishing move, due to this Hawkins, out of frustration, walked out on the match with Ryder, rewarding Ryder the win via count-out but keeping the championship on Hawkins. NXT General Manager William Regal decided to step in and give Ryder a rematch this time at No Mercy in a fan voted stipulation of a Ladder Match, TLC Match or Steel Cage Match, ensuring that one man will have to be determined the winner in such stipulations. The match was voted to be a TLC Match by a landslide vote.
Following the October 13th edition of Raw it was announced that due to personal issues between the Burchill's (Katie Lea & Paul Burchill) and the team of The Great Destroyer & Toxic an eighth match would take place at the event. This would be a Mixed Gender Tag Team Match in which the winning team would earn the male member of the team an Intercontinental Championship Match. It was also added that if Toxic is the Diva's Champion going into the match her championship would also be on the line.
The event saw four championships change hands including a rare double change for the WWE Tag Team Championships. The opening bout featured 3MB dominating The Dudley Boyz with D-Von Dudley continuing to fail the team, after getting hit with a single finish from Slater, Bubba Ray dropped off the apron and walked out on D-Von, allowing 3MB to get the easy win. Following this match 3MB were immediately forced to defend against The Ascension in an Extreme Rules Match which 3MB promptly lost. Beginning The Ascensions third championship reign. The third match saw a surprise entrant with NXT General Manager William Regal stating neither Ryder nor Hawkins were proven to be worthy champion, he gave the shot to Justin Gabriel who had defeated Ryder on the previous NXT episode, making it a triple threat. Gabriel dominated the two and won the championship. The fourth match of the night saw Jaichi & Toxic defeat The Burchills with little to no trouble, Toxic getting the win with a Lethal Injection.
The second half of the show had Titus O'Neil retain the Intercontinental Championship against Tyler Breeze with two Clash of The Titus'. Paige once again defeated Kaitlyn to retain her Women's Championship, easily defeating her again and climbing the ladder to retain the championship. The first of the three main events featured Brock Lesnar dominating both Miz & Goldust to maintain his WWE Championship.
The second to last main event was a long back and forth match between Rollins and Triple H which featured Rollins doing everything he could to put Triple H away before finally pinning him with a Sethwalker. In the main event the tournament finalists faced off with Kofi Kingston getting the surprise win via a sudden Trouble in Paradise finisher to Aries, this marks Kingston's first NXT Championship and world championship reign.