He's a big part of Team Magnus, and today he gave the first interview from inside the World Champion's camp on the cheating scandal engulfing chess.
Magnus Carlsen's close confident and long-time second Peter Heine Nielsen told chess24's broadcast team in Oslo that cheating in chess is indeed a "big problem" and added that "it's a pity if that becomes the narrative".
The Danish grandmaster's comments follow 24 hours of fevered speculation after Carlsen resigned his Round 6 game against Hans Niemann in the Julius Baer Generation Cup after just one move.
You can read more about what happened and the reaction here.
Carlsen logged off without giving a reason why, but it is widely believed to be because he is convinced 19-year-old Niemann has used outside assistance to cheat in the past.
The American has admitted having previously cheated in casual games, but vehemently denied cheating in top events or against Carlsen. Like Carlsen, Niemann has declined to be interviewed about the wave of speculation surrounding him.
On Carlsen refusing to speak about it, Nielsen told chess24's Kaja Snare: "It was a surprising decision to me also, perhaps to some extent, but also I respect his choice not to talk about it and if someone from Team Magnus is to talk about it then it should obviously be Magnus."
On the shock resignation, Nielsen added: "It didn't come as a surprise to me, let's put it like that. But again, I'm employed by Magnus and I think it's important to respect the privacy he has as a coach and the confidentiality to talk to me so... I'm not going to tell you that."
Asked if he suspected Niemann of cheating, 49-year-old Nielsen said: "Again, it's not something I've thought a lot about. I'm known to be the last one to realise these things ... I generally try to expect the best of people."
Asked if cheating is widespread, Nielsen said: "It's a big problem in the sense that we don't know if it's widespread how widespread it is, that we don't know if we are capable of detecting it or not.
"My first World Championship as a second was 2005 when I was Vishy Anand's coach in Argentina and there was pretty wild speculation when Topalov won the tournament and started with 6.5/7. Some people said it openly, as far as I remember.
"It's been an on-going theme and it's going to be bigger, bigger obviously what with computers becoming stronger and smaller, so that is quite a thing. Also, there's interest in Ken Regan's interviews and podcasts and things like that.
"Obviously, it's a pity if that becomes the narrative for chess. For instance, for quite a while for cycling it was narrative that people were debating that, and that of course is not ideal.
"It is not a new topic in chess, it has been going on for a long time, there is no doubt about that. In 2005 with Topalov and Kramnik, of course, but there have been numerous examples."
Nielsen welcomed the discussion saying "it's good, it's something that should be debated in the chess world."
"It's normal that it becomes an emotional topic and an important topic. This was also the case when we have seen similar discussions in the past."
Carlsen still hasn't made any public allegations of cheating, directed at Niemann or anyone else, and his social media has gone silent since the row broke out.
Asked if he knew if Carlsen will make a comment, he said: "No, that's up to Magnus."