That's a long one. The main issue is that they're both manipulative fags with massive egos.
The definitive moments in the feud were when Doug didn't advertise Comicsgate during an award ceremony and when EVS used Doug's anti-homo views as an excuse to denounce him.
@Mister Dongs might have more insight.
Doug TenNapel was part of the second wave of comic book professionals who, seeing the money that amateur projects by untested creators was bringing in, decided to hop on into CG back in 2018. Ethan played up what a victim Doug was to the people, describing him as an impoverished wretch who was brutally buck broken by the libs and who needed his and Comicsgate's help to get on his feet again or else his broke ass will be shaking a tin cup on the curb like a homeless bitch. Apparently Doug, a proud man, was not appreciative of this presentation of his plight, or at least not as appreciative as Ethan figured he would be. Publicly though, he sucked it up if that's what it took to get the project funded. Doug's intentions were, allegedly, more along the lines of using his crowdfund project
Bigfoot Bill as a proof-of-concept to then take to Activision and renegotiate his IP rights with
Earthworm Jim to trade his video game royalties for the ability to independently create and sell EWJ comics. In time,
Bigfoot Bill was created, a beautiful painted hardcover with gilt edges, made a lot of money and was an overall creative and professional success. That done, Doug slowly started to ease in the idea in backrooms (according to EVS) that it was time for he and Comicsgate to part ways, sweetening the pill by saying it wasn't
his idea, but that his agreement with Activision demanded no CG association. This was latched on to by CGers that hated Doug, like Cecil and EVS' goonsquad Warcampaign, that Doug was a traitor who was simply there to use CG as a cash machine, and Doug's anti-homo stances were counter to supposed Comicsgate tenets of apolitical centrism. But mostly because he acted like a smug dick who "thought" he was better than them. Ethan sat on the fence for a while until at Doug TenNapel failed to thank him on a SDCC 2019 "kings of crowdfunding" panel for 2019, after all he did for Doug. It was on now. FUK DUG. WE'RE A HATE GROUP? UR THE HOMO HATER.
At this point, Doug started burning every bridge he could get his hands on, yelling that he was being pushed out by SJWs yet again and was not in fact leaving of his own volition, and that even if he wasn't he'd have nothing to do with such a corrupt and vile anti-Christian group that he learned CG to be. And besides that, he never had any intention of being some youtubing grifter overcharging people $25 for comic books, but an artist giving true value to his treasured customers. Since then Doug has gone on to put such beliefs into practice, like building a 500K subscriber QAnon youtube channel claiming that the 2020 election was going to be overturned any day now
, selling NFTs for hundreds of dollars a piece, and hanging out with Dick Masterson. Comicsgaters continued to harangue the traitorous 'Dirtworm Doug' wherever he went online for years. Crucially, The Dick Show always had an open door for Doug until the 2020 election happened and Doug was able to finally build his own platform. One major consequence of the rift was that a lot of the socially conservative-minded CG creators left with Doug, which was a shame because that included most of the actually talented ones, leaving EVS with nothing but his beloved retarded freaks and grifters.
Since then Doug TenNapel has done various minor things to tweak Ethan and Comicsgate in repayment for all the shit they've given him over the years. One good example was mailing some original Earthworm Jim artwork to Thomas Roiloup to purchase
some of Ethan's Cyberfrog commemorative coins. A deep dive into the coinage was commissioned by the autists, and it was found that 'RibbitCoin' was minted in a Pennsylvanian facility that did not work with precious metals, making the frog coins fraudulent nickel presented as silver. This led to CG termagant VikkiVerse making her debut video about the RibbitCoin expose, which led to
@FROG dressing up in a carnival outfit address the accusations of fraud and accidently disclosing his deep ties with Dynamite Comics as he threw them under the bus for the fuckup. Which led to an industry-wide scandal at a major comics publisher secretly working hand-in-hand with Comicsgate and then being forced with a threatened walkout by their own employees
to release a press statement confirming their severance of relations with CG. Which in turn led to (another) civil war between EVS and his fan group in 2020. Such is how things go in Comicsgate.