Dexter "Dex" Manning is a good friend of everyone at Cow Chop due to him originally working with Aleks, James, Aron, and Joe when they all were employed at The Creatures (And possibly knowing Brett since they both worked for the same company). He is the Co-Star and Creator of the popular Machinima series, "Sanity Not Included" which also Co-Starred Aleks during Season 4 and so on.
Dex has worked on and been in videos with most of the guys at Cow Chop in the past (Excluding Brett, Trevor, Anna, and Asher). He created Sanity Not Included with Lyle McDouchebag, and when Lyle was fired from the show they replaced him with Aleks (James has also done some voicework for the show as extra characters).
As a Creature
In 2014, Dex started to become a regular on the channel for The Creatures, appearing as a guest on Creature Talk twice, a Creatures Play video, First Five, a Creature Short, and two movie trips. In Creature Talk, they mentioned that he helps with TR4PVILLE. Because of his numerous appearances on the main hub channel, many fans believed that Dex would eventually become a Creature. This was in fact proven to be true when he was inducted into the group at RTX 2014.
Dex was announced as a new Creature at their RTX 2014 panel . He confirmed it on Twitter along with this video, which was uploaded by a fan on YouTube, an excerpt of the RTX 2014 Day 1: Valhalla on Twitch. His YouTube channel link was added to the default video description the next day. James confirmed that Dex would be going back to England and preparing to move out to work out of the office. Originally, Dex was supposed to move the week of PAX Prime, but he ended up staying longer and visiting the office again for 2 weeks afterward.
He announced on April 20, 2016 that he was leaving the Creatures due having issues with being mistreated as an actual "Creature" during his time there. He mentioned in his departure video that he was disregarded and only viewed as an employee rather than a friend (This is referring to the Current Creatures, not regarding ANYONE currently at Cow Chop) as well as being forced to be politcally correct. His ideas were not noted and he wasn't treated like a "Creature" compared to the rest of the main "bosses" (He despised the dynamic of having four bosses). Dex was the subject of misstreatment by both Kootra (Jordan) and the Creature Fans, who made him feel unconfident for the first time as well as made him loathe being a "Creature". He though did not regret his time due to working and dealing with this problematic experience for the first time (Jordan tried to change who he was both as a onscreen talent and also as a person). This then led to even more hate towards The Creatures before the departure of Aleks, James, Aron, and Joe occurred during the same week period (They left for other reasons though).
He had no quarrels with Cow Chop due to Aleks and James backing him up against Jordan.
Channel Suspension & New Channel
On September 12th, 2014, Dex's channel was suspended for two weeks due to a copyright claim by Ryan Bane, who Dex used a video from in one of his Cringe Factor episodes and in another video, the latter being the one which ultimately led to the suspension.  Dex would later learn that YouTube suspended his channel indefinitely due to alleged viewbotting.  Shortly after learning this, Dex created a new channel to replace his old one.
On September 29th, 2014, Dex officially kicked off his new channel with a Dexplay video. He has also made a separate channel specifically made for Cringe Factor. His old channel was reinstated but he claimed he would still be using the new channel. 
Many people questioned if Dex was going to ever join Cow Chop because of the departure of both of them from The Creatures was roughly in the span of one week. Dex replied to such comments being that it is "James and Aleks' thing". Like James said in the first Cow Chop Q&A Livestream, he wasn't going to get all the former people whom worked with them to be in Cow Chop. However that always intrigued fans more to have Dex be a guest.
The hype for Dex was strengethed during the BLACKOUTS AND DRUG ADDITION Heavy Rain episode where Aleks looked into the camera and said, "I look like Dex. I look a little bit like Dex, don't I?" And proceeded to mock Dex's accent. This small bit in the ending crawl got people to want Dex to be on Cow Chop, leading to Aleks responding to a Twitter message about this topic. He said "I was really channeling my dex here" which then caused the actual Dexter Manning to message back to Aleks with, "when you goons flying me out" (Nov. 14 2016) . This then prompted messages from Cow Chop viewers on YouTube, Twitter, and Reddit to have Dex be featured in videos.
December 4th, 2016
On Twitter during this time period, Dex Tweeted out to Joe that he was flying out to Colorado. This of course was an alarming surprise to both his and Cow Chop's fanbase. He then started to release Tweets showing himself at the Cow Chop House' as well as James releasing photos of him there .' Brett also showed videos and images of himself, Dex, and the rest of Cow Chop hanging out via his Snapchat Story . This included them hanging around in a Bar, in which Dex still maintained his highscores on the gaming machine there, and also Trevor giving Dex a house tour (With Joe filming in the background. This is 10:00 PM 12 6 2016, No footage of Dex has been released on Cow Chop as of now. Only relying on everyone in Cow Chop's and Dex's social media feed).
Dex proceeded to respond to fan messages on December 6th, 2016 (4:25 PM) that he is NOT joining Cow Chop. He mentioned in his Twitter post: "Look, I'm not joining cow chop. They flew me out for some videos and to chill, we're close. I'm just here on vacation guys. So please stop ". This is obviously because he said he was never considering joining (Via his previous livestream videos) and also since he has a better line of work back in England.
December 12th 2016
On this day, Dex happened to appear on the video entitled: How To Make Christmas Dinner . During the course of the video, Brett served his "Christmas guests" food concoctions while the rest tried extremely hard to consume all the meals. From spicy sauce and dog food to rattlesnake and tarantula meat, they ate it all. Dex, Joe, Aron, and Aleks (With the exception of Brett who did not try all the meals) all tried the bad food. In the background Trevor was screwing around while Asher ate some fried bugs. Like Dex's show "Cringe Factor ", this Christmas Dinner video is in the same stylistic format making Dex really fit in with the guys at Cow Chop.
July 10th, 2017
On a Twitch stream that occurred on this day, Dex happened to reveal some facts concerning his experience with The Creatures. At approximately 1:40:16, Dex answered a question from Twitch user riperino44, stating "what happened with stefanie james and jordan though". Dex recanted from his recollection that nothing has really happened between James and Jordan as far as he knows and he doesn't understand why it is believe James and Jordan have a beef. However, despite not necessarily understanding or least acknowledging a conflict that James and Jordan supposedly had back then, he is sure they had beef in other ways, being that James did leave in a somewhat 'abrupt' manner.
Upon addressing his relationship with Jordan, Dex said he would in a way tolerate hanging out with him in a general sense, but he wouldn't "choose to hang out with him". Now at the time of Dex's personal tirade of his ex-coworker Stefini, he starts off with stating how she started at The Creatures as an assistant (as far as he can remember) and that, in Dex's words, "...had to sign a contract or some shit saying that she won't fuck anyone in the office...". However, Stefini and Jordan broke said contract and ended up going out with each other, implying that Jordan and his personal relationships are voided from contracts. This event caused many of Jordan and Stefini's co-workers to become frustrated. According to Dex, Stefini had influence on Jordan about her role in the company.
Dex pointed out a time in 2015 when The Creatures went to E3 that he says was his biggest beef with Jordan. On stream, Dex said "Jordan booked a hotel room with me for some reason...only booked it with me, because I knew he and Stef were going out...the only reason he booked it with me, is so he could sneak out of the hotel room and fuck Stef". Along with this instance, Stefini was meant to be managing the company's PR at the event, but ended up hiding behind Jordan the whole time.
Beyond his antagonistic aforementioned point of views regarding some of the members of The Creatures, he "doesn't get why the fuck people give Dan so much shit" and feels like people "need to fucking leave Dan alone a little bit in (his) opinion" because Dex feels like Dan didn't play that much of a part in The Creature's downfall. He believes that the downfall was more of a collective fault, rather than a few simple scapegoats.
Dex began to feel bad he would talk bad about The Creatures, and decided to provide his own scenarios (01:47:05) where he messed up. One of these instances is where he slapped Spencer in the car on the way to E3 because he was being annoying and Dex wanted him to shut up. This is what he deems is the worst thing he did. He then goes on to admit that he was constantly drunk. He states that the reason for his drunkenness was to rebel against the lack of power he had. To go along with the lack of power statement, Dex told a story where The Creatures were on a train; Dex said "dammit" and this caused Jordan to get offended. Dex then turned around to the family behind them and asked if "dammit" was a swear word, this caused Jordan to become annoyed. Dex goes on to say, even though Jordan states he does no swear, Dex claims he does and even hears him say "faggot" quite a few times.
Dex's rant on The Creatures ended around the 1:52:00 mark.