Fiendish Hellfire Core drop rate is 100% at the moment, which will get cut down to 1% once the next expansion hits.
World of Warcraft(Wow) Fiendish Hellfire Core - Gul'dan Mythic Mount Rewards:
- Fiendish Hellfire Core rares Mount
Raid takes around 30 minutes.
World of Warcraft(Wow) Tomb of Sargeras Set (T20) Rewards:
- 4 or 6 parts of tier 19 appropriate for your main spec
- Mythic achievements from Tomb of Sargeras
- 4 or 6 parts of tier 20 appropriate for your main spec depends from options.
- Character level 110.
Boost takes around 1-4 raids.