About the Old school oath neack

[Yagumi]

OK so i have the old school oath neck at stage 9and i wanna  upgraded it to 10 so i can salvage it  for the  crux for my prof. neck  HOWEVER the breakthough  neack is a oblivion necklaces which can be found in DT. My question is is there another place or a merchant that i can get this from besides DT

[Grimoir]

Unfortunately no. Only as a drop from DT