Dexter "Dex" Manning is a former-Creature. He is the co-star/creator of Sanity Not Included, which originally co-starred Lyle, but then changed to ImmortalHD when Lyle left.. He was announced as a new Creature at the RTX 2014 Creatures Panel, following a visit to the office in Colorado and after appearing in much of the Creature Hub's YouTube channel content prior.
Dex was an old friend of the Creatures, as he was a member of Kootra's Kool Klan. He is known mainly for being the creator Sanity Not Included with Lyle, when Lyle left he was replaced with Aleks. Several Creatures have regularly appeared in Sanity both before and after Lyle's departure. Once, Dex stayed over at Immortal and Sly's house and made a brief cameo on Minecraft Daily.
In 2014, Dex started to become a regular on the channel, 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. 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.