Bloodthirster

In a nutshell: The big bad Khorne flying monster. Your typical Monstrous Creature, with higher than normal strength and number of base attacks. Also is max weapon skill, so he hits most models in the game on 3+, which is normally good. He's been buffed with a higher than normal I value, and furious charge. His true cost to the veteran player is 270 points, you must buy Unholy Might. Base strength 8 means instant death for many characters, you wound virtually all MC on 2+, and when you charge normal vehicles you will pretty much autopenetrate all of them. I'd really recommend Blessings of the Blood God for 5 points, because for 5 points you won't get mind war'd. The biggest bonus however is a 2+ save against wounds caused by force weapons--NOT just using the force weapon as a psychic attack (he's immune to that anyway) but because the wording says 'wounds caused by'. So Grey Knight Grand Masters better have a Daemonhammer and will likely lose the combat anyway, but if they have just the standard force weapon...good luck.

Pros: Big, mean. Flies, a big bonus for Daemons who are usually slow. Immense strength lets him crush tanks, something Daemons lack.

Cons: Not enough value for the points cost. 275 points and a 3+ save with 4 wounds? Easy to drop that. Ask any Tyranid player why they run 3 Dakkafexes, 2 Gunfexes, and 2 Tyrants. One or two is easy to kill! 7 or 8? Not so much. One pathetic shooting attack that should have been included in the base cost, fast skimmers are very frustrating for bloodthirsters.

Tactics: Land at 12-15" from the enemy, you should be safe and still be able to charge something next turn. If you can't, fly + run is alot of distance followed by another fly + charge the next turn. He is a primary tank hunter, do NOT let him get bogged down killing fearless models or in a swarm of enemies. There are other parts of your army that do this better. He is not very good against tanks that move 12" or more, because of his lack of re-rolls to hit.

Final word: If you have the model already, fine go ahead and use it. It'll scare the noobs a while, then it won't and you'll start becoming frustrated. Best to leave this guy at home and pick another HQ choice who doesn't cost so much.