So here's a problem. Lord Kroak is standing next to some Saurus Guard. The guard have a rule:
His opponent has a unit within engagement range of Kroak and the Saurus Guard, and (not unreasonably) wants to finish off Kroak He'd quite like to get rid of the bodyguard first to prevent Kroak passing off wounds to them. At first glance this would seem to be resolved by Core Rules 1.6.2.
So whoever has the turn can decide which wounds get resolved first - this is certainly how I've seen this situation resolved.
This is however, wrong. Let's turn to the core rules again - the rules of interest being in sections 12, 13 and 14.
How to Handle Bodyguards When Attacks are Split
Let's imagine Lord Kroak, standing next to 2 Saurus Guard. A unit of Vindictors is postioned to they have to split their attacks, and they want to kill Kroak.
They split their attacks - 7 into Kroak and 6 into the Saurus Guard. After all the attacks are completed, 5 wounds are inflicted on the Saurus Guard, and 5 on Lord Kroak (Core Rules 13.3)
The 5 wounds inflicted on the guard would be sufficient to kill them all, but they are not yet allocated to the models.
The Seraphon player now has to allocate the wounds inflicted on the units to the individual models (Core Rules 13.3.1)
He chooses to allocate them to Lord Kroak first. Using the “Selfless Protectors” ability of the Saurus Guard, 3 of the 4 wounds inflicted to Kroak are transferred to the Saurus Guard unit.
Before you allocate a wound or mortal wound to a friendly Seraphon Hero ... On a 3+, that wound or mortal wound is allocated to this unit instead.
- Note - to the unit, not to a model within the unit. So the wound joins the pool of wounds on the unit, ready to be allocated to models inside in a sequence of the defending player's choice.
The remaining wound is then allocated to Lord Kroak (Core Rules 14.1).
The 6 wounds inflicted on the Saurus Guard unit are now allocated to the models in that unit, killing them both (Core Rules 14.2) (If the unit had a ward save, then the non-transferred wounds could potentially be negated at this point).
The excess wounds are negated (Core Rules 14.1). I found this a surprise
The key here is the difference between inflicted and allocated wounds. For a given unit's set of attacks, all wounds caused are first inflicted on a unit, then they can be transferred if a bodyguard rule is present (to be inflicted on another unit), then allocated to models (where if a ward effect hasn't been previously used they can be warded) - models allocated more then their wounds characteristic are removed from play.
We usually don't go through all these steps - because most of the time the sequence runs through uninterrupted. But the presence of a bodyguard rule such as Selfless Protectors makes knowing these steps necessary, to get the process right.
How to Handle Bodyguards When Attacks Are Not Split
There is an alternative situation. Imagine those liberators can all reach Lord Kroak, and put all their attacks into him, ignoring the bodyguard.
All 10 wounds are now to be allocated to Lord Kroak. One at a time, for each wound he tries to pass them off to the 2 remaining models in the Saurus Guard.
But look at rule 14.2 again
Once the number of wounds allocated to a model equals its Wounds characteristic, the model is slain. A slain model is removed from play (see 1.2.2) after all of the wounds allocated to its unit have been allocated and all attacks that inflicted damage on the unit have been resolved.
Unlike the previous situation where both Kroak and the Guard were targeted, now the guard is only receiving transferred wounds. They come in one at a time (you have to assume slow rolling when working out how to apply the rules (13.2.1)). Each time the wound arrives at the unit there are no more outstanding attacks affecting the guard, so the wound moves directly to a model (without a chance at warding (14.3 FAQ). If the wounds inflicted on the model exceed the Wounds characteristic, it is slain and removed.
That means that once the guard, in this scenario, have taken 4 transferred wounds the models are all removed, the unit is destroyed, and Kroak has to take the rest of the wounds himself.
Let's revise that point from earlier:
How Do I Remember All This?
It's pretty challenging to think through - and moreso to explain to your opponent who might not want to know this, and to stick with rule 1.6.2, especially on their turn. They're also likely to find the idea that a bodyguard can absorb more wound than they have particularly disturbing.
Here's a handy flowchart for how to allocate wounds, annotated with the relevant rules.