Background Material Evaluation.
The first legion that I'm reviewing from Retribution is the White Scars Legion. Now, the key thing to realise is that Retribution does not give a full overview of the three legions it presents like the other volumes in the Horus Heresy. Hence, we're lacking the key battles that they've fought in, how their Primarch was found, and all that juicy kind of detail that I sincerely hope gets published right after the Space Wolves and Thousand Sons in the next volume.
That said, we already know from "Scars" (Black Library) that the White Scars Legion were the path finders of the Great Crusade. They harried the bigger targets whilst destroying the easy ones. This left a great vacuum in their wake that subsequent follow-up by other fleets and components of the Great Crusade then exploited as the White Scars moved rapidly on to their next target.
We also know of this Legion's predilection for riding bikes and moving very quickly in general. This, I feel, is very well encapsulated in the rules presented within Retribution.
Legion Rules Review.
The first of their special rules is Swift Action. By moving their full range in the movement phase (6 inches for infantry, 12 inches for vehicles) the White Scars can re-roll to wound rolls of 1 and gain a +1 to their cover save for the entire game turn. This is very powerful in its own right, but merits strong planning. One has to remember that units like jet bikes for instance must move in a straight line, hence a little bit of planning at deployment can pay dividends on turn one. Of course, the inference of this special rule is that heavy weapons that can't be moved and fired at full ballistic skill in the same turn should probably be avoided. Leave such weapons to other legions and play to the strength of your fast moving White Scars!
Eye of the Storm provides a pip bonus to seizing initiative, going first, reserve rolls (only the first per turn) which is a very nice boost that can compete with Alpha Legion rites of war when combined with other methods of doing this (cf. Land Raider Proteus).
As might be expected, the White Scars are all skilled riders thanks to Born in the Saddle.
Finally, To Laugh in Death's Face means that a fast attack choice must be taken before a heavy support one. Fair enough really considering how one might typically build a White Scars army list any way.
Strikingly, there are no negatives for this legion which makes them incredible and unique in so many ways.
There are two items here to discuss.
The prime one is the Power Glaive. For the same option as a power sword, a White Scars characters can get a versatile weapon that can be AP3 or AP2 (with +1S) depending if you use it one or two handed. This is a great boon and should almost always be taken by a character if they're not going to go down the power fist route. And indeed, with a bonus to re-rolling wounds, the AP2 with bonus strength is going to be wounding most of the time!
The second is really interesting, and in the form of a Cyber Hawk. This is for a Praetor level character only though. What it does is to place a marker (the Hawk) anywhere on the battle field. White Scars then get a bonus to hit against any unit with 6 inches of this marker. Plus it can provide a re-roll to charge distances. This is incredibly powerful (particularly in combination with the Swift Action rule) and should almost always be taken by a praetor. It is also incredible strategic and should be thought about clearly. Place it next to the first target for shooting on turn 1 and the Swift Action toward that target and shoot at it. This is almost better than comparable shooty legions to be honest.
I will look at Legion Rites of War later in a different article as Retribution provides a new proliferation of these above and beyond what previously existed within the other tomes.
Overall though, the White Scars are an excellent and swift moving legion that begs to be used on bikes, jet bikes, and with cyber hawks from a praetor to take out a target unit every single turn whenever possible. I can see them being a huge pain for slower moving legions and armies that just can't keep up. They will even give certain Eldar builds a good run for their money despite being the top 40k codex (at the time of writing). I'll write up example army lists at a later date. This army is incredibly powerful, make no mistake, and I believe one of the top tier Horus Heresy armies when built well and played well.