Just adding to what Nekonarf said - TH has absolutely no effect on Defending Ring dropping or not. KB will ALWAYS drop either ring or Pixie Earring, with the latter having a much higher drop rate obviously.
Grats man, idk what the deal is with dring lately but 3-4 dropped on our server in the last month. 2 of our ls mates got 1/1 on it. Ninjad drop rate or pure luck.