Here's what we got so far...

Emotes:
coughs something up ---> He casts curse
extends his claws ---> He casts Traumatic swipe (single target trauma, good idea to cure very fast) Then, most of raid may or may not get razor claws (bad incurable trauma dot). Not sure how to avoid it but jousting sometimes helps. however, jousting often leads to curse spreading.
opens his jaws ---> incurable elemental on tank, hard to avoid death if hits.
hhhhhhiiiiisssssss (sp?) Not sure!

hmm okay... Do you remember which emote... he seems to have a few different emotes that he does.

Claws are a tankdead special from Rarthek, tool this. The elemental reduces the migitation of the tank (only one gets it). But can be avoided when moving. All specials hit 4 secs after the emote.

got all that but getting some effect called "razor swift claws" that does massive damage and can't tell where its coming from...

Move tanks before you get the elemental? which effect are you talking about... maybe this is the thing we are missing.