He is (more or less) the one who broke up Seremedy. It happened along with their gig at Närcon (I think, someone with more info can correct me) where Seremedy were booked for about 25,000 SEK. This gig was booked 6~ months prior to his debut in Melodifestivalen, but the gig was a month or two after Melodifestivalen. Yohio told the Närcon group that he wanted to change the contract and recieve 125,000 SEK for the gig (if I remember correctly) since he was famous now. And as they didn't want to pay that, Yohio decided to not attend the gig with Seremedy, resulting in the band cancelling the gig and the members of the band fighting. He also went out in Aftonbladet (famous swedish newspaper) and said that he made himself famous in Japan with no help at all, and the reason to Seremedy having fans there was because of him. This made SEIKE (ex. Seremedy) pissed off (since he was the one who had contacts in Japan, not Yohio) and resulted in Kerberas first single, which is about him.
I have pictures of him sent to me by friends as recent as from last weekend, with Yohio and his bandmates all drinking alcohol and smoking. I'm not posting them though, obviously.
Yes, the topic I linked just repeats what I said in my previous post, but in Japanese. I have friends who I trust dearly in Japan who have experienced same thing as the gya's in the topic, so I don't doubt it for a second. On the swedish forum "Flashback" there's fans of him who has written about their shitty sex, and as Emmny said, there's dickpics as well that he have sent (which originates from Flashback). Regarding sexism, just read some interviews in Swedish from 2011-2013. He mentions Lady Gaga and Nicki Minaj several times during those years.
The last part would probably just be considered rumours to someone who don't have any proof, but I can assure you it's true but it's up to you to believe what you want of course. Also, just like Euthanasia said, he's not the only douchebag in Disreign.
Of course I respect and have no interest in changing your opinion either, just saying why I dislike him. Despite what a shitty person he is, that is not the main reason to why I don't like him. The main reason is that I don't like his music, which I wouldn't see a point in listening to EVEN if he was as good as your basic visual kei band.
EDIT: Also, considering how irrelevant he was in Japan until he moved there and started sleeping around just prooves how good PR he had to trick the entire Swedish population into believing he was some big shot superstar who had made it in Japan.
EDIT 2: Don't get me wrong though, he's still irrelevant. Just not ~*as much*~