There are a whole lot of misconceptions about how Soul Link behaves, both in Cata and in MoP. Many players like to think of the Cata Soul Link as a straight 20% damage reduction. The reality is that Cata's Soul Link is sort of an elaborate absorb shield, which partially defers damage to your pet, which then usually gets healed by talent effects.
For MoP's Soul Link, let's first look at the tooltip:
Requires Level 45
100 yd range
10 sec cooldown
When active, all damage and healing you and your demon take is shared,
but your demon's health is reduced by 50%. Recasting this spell cancels
the effect. Replaces Health Funnel.
The most common reaction to MoP Soul Link's tooltip is something like:
Wait, shared damage and healing? You mean that if someone attacks my pet they'll hurt me? And my pet will reduce the healing I take? AND my pet is 50% weaker? AND I can’t even heal my pet? Gee, thanks for the nerf Blizz! Give me back my damage reduction! >:(
true, that's a pretty bad perspective to take here. A much more accurate (and positive) perspective would be to think of Soul Link as an effective health increase equal to 50% of your minion’s health, which is also shared by your minion. I think I’ve spent enough time talking about surface perceptions, so let’s get into the hard mechanics.
First, there’s your minion’s health to take into consideration. In MoP, your minions have a flat percentage of your total health:Imp: 30%Felhunter, Succubus, Felguard, Fel Imp: 40%Voidwalker, Observer, Shivarra, Wrathguard: 50%Voidlord: 60%
As you can guess with a little math, your minion would have between 15-30% of your max health with Soul Link active.
Second, there’s the damage and healing split, which is where things get tricky. Soul Link doesn’t split a flat 20%, or even a flat 50% of your damage and healing. Instead, it uses a ratio based on you and your minion’s current health compared to your total combined health.
For the sake of easy math, let’s assume you have 100k health, and you’re linking with your Voidwalker. Using the above health scaling percentages, your Voidwalker should normally have 50k health, which is halved by soul link to 25k. So, your combined health pool while linked would be 125k. Now, let’s say you’re at full health and take a 10k hit, how is that split up?
100k/125k=.8 and 25k/125k=.2, so the damage is split 80% to you and 20% to your Voidwalker, or 8k damage to you and 2k to your Voidwalker. But what if that attack hits your Voidwalker instead? The ratios don’t change at all, so 8k still goes to you and 2k still goes to your minion.
Now, let’s say that for some reason or another, you’re at half health but your Voidwalker is still full. The ratios are now: 50k/75k=~.66 and 25k/75k= ~.33, so a larger percentage of the damage is going to your minion instead of you. If your health somehow goes below your minion’s, then the majority of the damage you take will go to your minion instead of you.
Healing works in a similar way, though it uses your amount of health lost
. So, if you’ve lost a greater percentage of your health than your minion has, you’ll receive more of the healing. One interesting advantage to this split is that if say the minion is at full health, and the ‘lock is not, then all
healing to either
target will go to the ‘lock (or vice-versa) without overhealing until both targets are full.
Do you see what I mean when I say that Soul Link acts like an effective health increase? All damage and healing is split in such a way that it affects the total pool more than the individual ‘lock and minion pools. Except under extreme and unusual circumstances, you won’t die until you take more damage than your total combined health pool.