Mithun C. is the Grandmaster. He's there because I believe the concept of the show is his...and well they go on the "Disco Dancer" craze he created back then. He does judge but he's mostly there for support, to make fun of judges/Jai (the host), and flirt with somebody or the other 😕😆..he can make the big decisions like veto amongst others but he does not actually give marks--just kya baat kya baat kya baat or a grand salute to appreciate good performances.
Actually none of the DID judges (Remo, Geeta, Terence) give official marks like they do in JDJ. They just critique the dances--point out negatives and positives. The only time I remember them giving marks was in DID1 when they would just say what scores they would give the contestants.
They're giving marks in DKS because the format is such that a team will win every week so they need marks to decide which team will win.