Does NRG mada mean Derke will move to Vitality?

Derke's potential destinations were Vitality or NRG, but NRG signed with mada.

yes it is confrimed

Pretty much yeah I think. All rumors pointed that Derke would join either NRG or Vitality so unless there's some secret 3rd team or some org quickly finished the deal and paid much, he should be joining Vitality.