I used to be a regular on DS, a long time ago now. I remember 5371Robert or whatever he was called, the prototype incel who was insanely jealous of his sister and couldn't get a girlfriend. At about the same time, there was LostPigeon, who posted strange videos of himself on holiday and said "coo" in his posts a lot. I think he had at least one other account, as he'd occasionally post a link to the Daily Mail with no "coo", and using normal English.
We also had Dream Stuffing, who had a weird sexual fetish about schoolboys and boys in sportswear, who used to get in arguments with ForestChav, another poster who was a bit too interested in teenage boys. Dream Stuffing was all over every discussion forum going at one point, until he suddently disappeared. I think he got put in jail. I'm sure I remember him admitting he was on probation, or had some sort of community order stopping him from going near schools.