Versus such comps with high burst and mobility and a great cc chain. You want to start defensive while still playing aggressive on the ret. Trust me, if you sit on that retribution paladin, while still applying chains of ice on the death knight to peel him off your healer or you. The paladin will use his freedom on the death knight and youll be completely free to fully control the ret while doing enormous pressure, with necrotic strike. When you play versus such a high burst comps, never, I repeat, never use an offensive AMS unless you are 100% sure you will get a kill. If not, dont even hesitate, one hard swap on you will kill you within a couple seconds if you have no AMS. If you see the ret and the death knight triggering their cool downs, dont just pop AMS either. First youll use AMZ, anti-magic zone. This will stop the first burst, and give your healer time to actually sit a HoJ or sit a Strangulate. If your healer is HoJd and you are In AMZ with like 60% HP, I can guarantee you that you will survive. Thats when your healer will use an instant heal or a defensive ability such as HoP, HoS, HoF, Or any priest Shield/damage reduction such as pain suppression. This will make him able to sit another cd while you being perfectly safe. Now you can slowly play more offensive, pop unholy might (if not yet used on your healer to break Repentance), to increase your damage and start stacking a couple necrotic strikes, If you see a WoG. Than now is your chance to get a kill in there. Pop Gargoyle, pop offensive trinket, stun the paladin and start destroying the death knight. The paladin might even bubble here, or trinket the pet stun, if he doesnt make your healer use another cc. Which will leave him defenceless if he trinkets go back on the pally and drain him. You still got 2 minutes(1min40sec actually) before he can do any sort of big burst heal or big burst damage. So youll taking over in those +/- 2 mins. The death knight will try to peel you off, try to make your healer. As we all know, unholy has very high pressure, if your healer supports you well, you can trigger a bubble from the ret. After the bubble, its over. Because you can mass dispel if you have a disc and or follow it up with a strang+ pet leap+Pet stun+Healer cc.
If you also play ret/dk, itÔÇÖs pretty much the same except you wonÔÇÖt have much time to think. You have to put higher pressure as the death knight in order to make the enemy ret pop his cool downs faster than you. There isnÔÇÖt much to say.
So thatÔÇÖs pretty much it. Of course in real combat itÔÇÖs a lot harder than this. But if you practice enough, even the strongest comp will become easy.