Edit: this post fell sadly out of date when the talent trees were reworked for Wrath of the Lich King. It's now of minor historical interest at most. I'm working on a new levelling guide but Please check our my rough guide to shadow talents in the meantime.
You pop shadowform for the first time. You hear that deliciously creepy hiss. You start to shimmer and descend into the churning shadows.
You have abandoned the Light. There is no turning back.
Your journey past level 40 is one of discipline and power. You will learn to channel your destructive energies with focus and efficiency. You are the angel of death: dispassionate and devastating.
This build assumes that you followed my spec up to level 40. If not, go respec now! Our aims remain the same — to level swiftly and efficiently. To this end, we need to put our talent points into two trees. We are going to focus firstly on increasing our damage output then return to the discipline tree for some talents to help improve our mana efficiency. So let's get started...
Levels 41-45: wand specialisation (discipline tree)
We made good use of these points before shadowform and we want to get them back as early as possible. Wanding is going to remain an important source of damage as you level to 70. Don't forget, shadowform affects shadow wand damage too so always try to pick up shadow wands.
Levels 46-50: shadow weaving
Five points in shadow weaving will ensure each shadow damage spell you land increases shadow damage taken by your target by 2%. This effect stacks up to five times, so can amount up to a 10% damage increase. In reality, you will rarely if ever get a full stack on a single target in solo play, so this isn't that useful as a levelling talent. But you need the five points to reach the next level of talents, and a damage increase of even 4-6% is not to be sniffed at.
Levels 51-55: misery
The inspiration for my blog, if only because darkness was already taken. This increases all spell damage taken by the target by 5%. Again, it's not going to break your solo play, but it stacks nicely with all your other damage multipliers. Plus, it's nice to have when running instances.
Level 56: vampiric touch
Another class-defining talent, this spell causes damage over time and returns mana to you and your party equivalent to 5% of shadow damage dealt to the target while the spell is active. We could have taken this sooner if we hadn't put five points into wand specialisation, but I think the wand damage is more important.
Levels 57-58: improved power word: fortitude (discipline)
This increases the effect of your stamina buffs by 30%. These next few talents in the discipline tree are fillers in a way — our ultimate goal is meditation. But as you head into Outland, the extra stamina is really quite useful.
Levels 59-61: improved power word: shield (discipline)
Increases the damage absorbed by your bubble by 15%. Again, a bit of a filler talent. You need to move to the next level and the alternative talents are even less useful to you.
Level 62: inner focus (discipline)
This buff gives you a free spell every three minutes, and increases that spell's critical strike chance by 25%. Shadow priests should only ever use this on shadow word: pain (undead may wish to use devouring plague instead), which is your biggest mana cost in any spell rotation. It's useful to bind it to the spell in a macro to ensure you get the full benefit. At level 70, it can amount to up to 15 mp5 if used in this way.
Levels 63-65: meditation (discipline)
This is the reason we have specced so deeply into discipline. Meditation enables 30% of your base mana regeneration to continue while casting. As you progress through Outland and collect spell damage gear, you will see your spirit slowly dwindle and this helps to balance the reduced gains from spirit tap. You may have worked out that this talent too will become less useful as your spirit falls, but that can't be helped. This is simply better than the alternative, which is no mana regeneration at all. For me, this talent currently equates to 46 mp5 but you should start off with considerably more.
Levels 66-67: focused mind
Now that we are done with discipline we can return to shadow. These two points will max out focused mind and ensure the lowest possible mana cost for your mind blast and mind flay spells.
Levels 68-70: shadow power
It's difficult to know what to do with these last three points. If you are planning on raiding at 70, you're going to have to respec anyway, which makes spending them at all seem rather arbitrary. If you find yourself running lots of instances in your later levels, then I'd recommend putting these last three points into shadow affinity, which will reduce your threat by 25%. But if your experience is anything like mine, you'll find it much quicker and more convenient to level through quests and grinding, in which case threat reduction is irrelevant. You could put them in improved mind blast to reduce the spell's cooldown, but it's not terribly good practice to spam mind blast anyway. So I've opted to put them into shadow power. Three points will increase the critical strike chance of mind blast and shadow word: death by 9%. That's a nice increase for three points, but you're not going to be using these spells a lot solo. It's a shame that a school with such iconic talents as vampiric embrace, shadow form, darkness and vampiric touch finishes so limply but I guess we can't have it all our own way.
So there you have it. Congratulations on reaching level 70. If you've followed my advice, your talents should look something like this.
This is a nice final build if you're going to continue questing and grinding solo. But if you are planning on running instances and gearing up for raiding, the next thing you should do is respec. This build already has the core talents of a raiding build, but we'll need to move a few points around to maximise our utility and damage. But that's for another post.
22 hours ago