http://www.icy-veins.com/wow/gorefiend-strategy-guide-normal-heroic
[video=youtube;cT07LTKpf5A]https://www.youtube.com/watch?v=cT07LTKpf5A[/video]
Key Mechanics
Tank swap: Shadow of Death (http://ptr.wowhead.com/spell=179864/shadow-of-death) will teleport the affected tank to Gorefiend’s stomach.
When in the stomach, tank the Enraged Spirit (a purple, transparent orc).
Avoid the Enraged Spirit’s Fel Fury (http://ptr.wowhead.com/spell=181282/fel-fury) by moving away during the cast.
Interrupt Bellowing Shout (http://ptr.wowhead.com/spell=181582/bellowing-shout)
At 70% life, the Enraged Spirit will escape from the stomach and becomes a powerful Gorebound Spirit that must be tanked. When this happens, exit the stomach by running to the structure in the middle.
Tank the Gorbound Spirit outside the stomach.
Tank swap at 10 stacks of Fel Flames (http://ptr.wowhead.com/spell=185189/fel-flames), or when your stacks drop off.
Feast of Souls (http://ptr.wowhead.com/spell=181973/feast-of-souls): Intercept the small purple sparkle adds (http://ptr.wowhead.com/spell=184437/unstable-soul) before they reach the boss. Intercept them away from the raid so no one else gets hit by splash damage.
Environmental Hazards:
Avoid purple swirlies.
Use avoidance mitigation to reduce the application rate of Fel Flames (http://ptr.wowhead.com/spell=185189/fel-flames) from the Gorebound Spirit.
Spec into controlled movement abilities to help you intercept the sparkles in the Feast of Souls phase.