I'm going to summarize this dude and partly because I'm on mobile and I might get lost in my endless block of text. A lot of my sources are taken from lolcow since they have talked about him far longer than PULL and has lots of evidences that I can use instead of looking for it myself.
He's currently the "game developer" of the debug build (not yet a game), Yandere Simulator . But before that, he used to be "Evaxephon" who pissed off people by spamming the link to his awful streams. He also used to frequent Gaia, where he was mostly known for complaining about the fact that he couldn't get a girlfriend. Here's why:
He had aspirations to develop video games and even tried to program a fighting game engine and was criticized by Mike Z., main programmer of Skullgirls . He made a big deal about it because Mike wouldn't give him a single praise.
His first Attempt to Make an Actual Game:
His first attempt to make an actual game was a side-scrolling hack 'n slash game called, Lunar Scythe the main character being the most edgiest-looking woman ever made so far being on a quest to cleanse the world of "human filth."
Check the story here: http://archive.is/33yOj
He quickly turned to a laughing stock when he kept showing everyone the same character drawn by different people over and over, ignoring what other people were telling him.
The Reincarnation of Evaxephon to YandereDev:
After god-knows-how-long time, Eva returned as "YandereDev" (some loyal fans affectionately call him "Devpai." A mix of "Dev" and "Senpai" apparently) with an actually interesting game idea were the protagonist is a stone-cold yandere who can't feel emotions and her objective is to kill (there are options for a less 'violent way' of eliminating rivals but the variations to do that are currently slim) every student in her school who has a crush of her senpai. Some person (I couldn't find the person's name/username in my source/s) liked the concept and contributed to the game, giving feedback and some volunteer work, but after a whilr, Eva couldn't help and throw hissy fits, like his attempt to turn the whole Mike Z chat into a sob story:
Eventually, it came to light that Yanderedev and EvaXephon were one and the same when an ex-volunteer leaked it:
He again, became a laughing stock but that didn't stop him from defending himself:
Up until now, he's complaining that he couldn't make any 'progress' to his game because of stupid emails by his 12 year old fans and made a youtube video about it (he has more videos about it tho).
He also pissed off his volunteers on a regular basis and pedophilia
Despite all this, he still manages to have a large group of fans ever since YanSim blew up when PewDiePie played it and he receives 5k a month on Patreon. And he also seems to have lost $500 on his Patreon when he proposed to implement a yakuza fighting stlye on Yansim but later apologized about the idea.
His personal site: http://evaxephon.com/
His Coding as a "Game Developer" is Questionable:
Someone pointed out at a screenshot of a code floating around on a video that didn't look like a seasoned programmer would type:
He only learned programming or whatever for 2 years and worked for companies with no name games. 2 years isn't even enough. You have to learn texturing, animations etc. No wonder he's a noob dev.
Others (Part 2):
People at lolcows actually found out this dude's real name. I won't post his personal info here but since this profile is public, then I guess I'm not posting against the forum rules. He actually authored articles about adult games/stuff.
Also, if you have watched the link to the video were he whines about stupid emails, the green haired character there is called "Midori Gurin" (means Green green in Japanese. lol) apparently symbolizes the annoying 12 year olds who wouldn't stop sending him stupid emails. Most- if not all- his characters in the game are actually "place holder" bought unity assets. So much for a game dev.
Fun Fact: There's so much stereotypes in his vision of the game. The "currency" in YanSim are panty shots, you can actually enlarge those poor school girl characters into big watermelons that could bounce off their chests if given the chance, one of the elimination methods is to make up rumors about your rival and if her reputation is low enough her desk will be vandalized and a flower will be placed on her desk (which is a stereotype according to lolcow users because according to them, japanese students don't do that in this era anymore since it will attract more attention). Oh yeah, he also made a character whose name literally says, "Mai Waifu" with long violet hair and rainbow (changing) eyes with big breasts. I would like to add that Eva has no real girlfriend but some fans literally thought that that character symbolizes Eva's GF in real life (I know because I used to be one of the believers). And a character whose make up style has fallen out of era (forgot what that style was called). Oh yeah, you can also change panties (your protagonist) that apparently can increase certain skills if you wear those interesting-looking panties.
He claims that Yansim will be finished in 2019 and will launch a kickstarter about it. Apparently it's to hire professional programmers and the like to help Yansim. Because he can't even make a single asset himself without buying it on unity or asking his volunteers to do it.
Friendly reminder that the guy gets $5k on his Patreon with the volunteers doing most of the work un-paid. Yet he still whines about stupid emails while implementing a total of 24 or more easter eggs in the build. His excuse was that it's for 'entertainment' and just some silly stuff he's adding to take a break from working on Yansim.
Gaia History (lots of screenshots):
Account (Part 2):
He actually has a fanfiction account that has really adult content in some of those fics.
(If you do not like... Adult stuff in fics, do NOT open the spoiler. It's one of Eva's fanfics that was archived by a kiwi user for "future generations" in case he deletes them some day. The title's called, "Deaf To the World." Nov. 26, 2011).
If you're interested about his debug build, you can check his Game Development Blog to check the debug build's progress. But if you ask me, I could go on to suicide mode by drinking a shot every time he lists down all the "bugs" he "fixed" or on normal mode, were I'll drink ever time he implements another easter egg. Seriously, this dude "fixes" a lot of bugs and posts them on almost every post he makes to make it look like he's "constantly" working on Yansim.
Others (Part 3):
Here's a link were he's "clearing up volunteer misunderstandings."
A pic of him not having any proper training in coding.
He may have legitimately harassed someone:
An ex-volunteer talking about YandereDev/Eva and why s/he quitted the team.
A 3D modeler who criticizes Eva for putting un-original characters in the build.
I'm pretty sure that it's just Yandere-chan's clone with different and re-colored hair, being the noob game dev he is. In fact, all of the characters in Yansim before were clones of Yandere-chan with different or recolored hair and all the males are clones of Senpai with the same work done to make them "look different." Even the teachers in the game are also base models of Yandere-chan. You can still see the previous builds being played by let's play youtubers if you can search 'em up because currently, all the character's appearances are now drastically changed thanks to his un-paid volunteers.
Another kiwi posted this (under spoiler) that was used to show off the official shirt:
Posts he posted here and here . Some pics to go along with it:
Some kiwi user leaked this pic to prove that s/he knows Eva. At first s/he was reluctant but finally leaked a screenshot of their conversation:
Funfact 2: Yandere simulator is banned from being streamed on Twitch. Gee. I wonder why?
When YandereDev/Eva implements a... Torture mechanic (currently you CAN torture your rivals but you can't SEE how they're actually being tortured) then it's going to be....
He got information from a real Japanese teacher and how sailor uniform outfits are only worn for elementary students.
He made a comparison video of Natsuiro High to Yansim (which also has panty shots. Go figure) and Hitman (you know, to copy some stealth elimination mechanic.)
There's some (probably as decent game devs than him) who started copying his ideas of the game. If he stops implementing easter eggs and actually learn up-to-date coding, then he'll finish the game before 2019:
You know one of those artists that are helping Eva are actually suspicious people with fetishes:
Some kiwi managed to screen shot one of Eva's past streams but he couldn't get any more because Eva deleted it. Eva started calling a girl "autistic" and threatened to dox her.
Stolen and Bought Assets:
Don't bother arguing with this dev about assets and stuff because he'll just say that it's a "place holder" and only "temporary" until he finishes the sandbox into a game. Here's a Japanese Clinic kit was probably taken from here.
Almost forgot, YandereDev/Eva has a neo-nazi supporter.
Some more stolen asset (he just literally recolored the hair): https://archive.is/7QRwV
"Info-chan" (who is like an anti hero is Yansim who helps Yandere-chan if she sends her enough panty shots): https://www.assetstore.unity3d.com/en/#!/content/11573
Yandere-chan's rival, "Osana Najimi:" https://www.assetstore.unity3d.com/en/#!/content/15653
All male characters: https://www.assetstore.unity3d.com/en/#!/content/15667
He actually admited that the characters are unity bought assets and that they're just going to be "place holders" in a blog post before. But I can't find the blog post because I'm flooded by a lot of the info that I'm trying to summarize him right now.
Another stolen asset: https://www.assetstore.unity3d.com/en/#!/content/13151
Also, he doesn't want to have problems with original characters to people who own said original work/s.