Tilley-Death Knight Tank- Scilla

[Lorake]

If you glyph Imp Rune Tap you get a little party healing, and any little bit helps, even if it seems minor. As an offtank your threat shouldn't be too much of an issue, since ICC does not possess any Patchwerk fights where OT threat is really important. Also, Mark of Blood would help with tank healing, and as a tank you shouldn't be relying and blaming healers for your death when you still have options available to help heal yourself (~10k healing every 30 seconds from Rune Tap really isn't something to pass up on). Also, Blood gets good threat anyway, as heart strike is plenty of proski threat.

PS Wowhead/link the unholy build you'd plan on using.