I believe his normal loot table is always this:
1 tongue
3 BIC quest drops
1 BP - totally random which one
1 leggings - totally random which one
1 wpn aug - totally random which one
For event information, see this quest entry.
The true Tunat hits up to 6.5k on max shielding tanks on the first 10% of his health (before he starts transforming).
Blade Warstone
Cracked Shard of Power
Dark Tunic of the Enslavers
Drape of the Merciless Slaver
Greaves of the Dark Ritualist
Greaves of the Tunat'Muram
Jagged Glowing Prism
Lightning Prism of Swordplay
Merciless Enslaver's Britches
Old Eternal Grove Plate Feet Ornament
Solid Stone of the Iron Fist
Tongue of the Tunat'muram
Tunat'Muram's Bloodied Greaves
Tunat'Muram's Chainmail of Pain
Tunat'Muram's Chestplate of Agony
Worked Granite of Sundering