Who is Kang Min-gu, who was fired for mentioning the "Jung Chung-rae faction"?

When Lee Nak-yon was doing well, he was a key pro-Lee figure along with Park Kwang-on
He was actively involved as the head of the 'New Welfare Forum' in Lee Nak-yon's presidential campaign
After Lee Nak-yon's downfall and the rise of the Lee Jae-myung regime, he served as a special advisor to Park Chan-dae
Lee Jae-myung likes him very much because he flattered him by saying "Lee Jae-myung is the father of the Democratic Party"
What's this about the "Nak-ji faction" (Lee Nak-yon faction)? The Nak-ji faction is swarming around Kim Min-seok's side