So how does the new Lightning Attack and Swift Attack come into play against hordes?

The rules for that are copy-pasted from Deathwatch and don't make any sense with the new ruleset.

www.fantasyflightgames.com/edge_foros_discusion.asp

Second post features your answer. To summarize: They stack. Yeah. Melee is the horde killer now, more or less.

Reverend mort said:

what does he mean "they stack"?

I go frenzy, I have 70 WS. I also have Whirlwind of Death. I attack a hord (+30) with Lightning Attack.

I woll a 32. How much damage do I make?

vogue69 said:

vogue69 said:

WS70, increased to 80 by Frenzy, reduced to 70 by Lightning Attack, +30 for Horde size. 32 to hit is 7 Degrees of Success, which results in 7 hits from Lightning Attack. It's also enough for three additional hits against the Horde (every 2 degrees, an extra hit inflicted, so 7 Degrees = 3 extra hits), so you've hit 6 times in total. Whirlwind of Death then adds 4 (add Half WS Bonus to damage against hordes) to that, so you reduce the horde's magnitude by 14 so long as those hits cause damage.

Check this out then:

WS 70 +10 Frenzy +30 All-out +30 Horde

I roll a 40 = 6 hits + 4 for Whirlwind = 10 hits

then (furious assault)

I attack again with the same 140 WS

and another +4 from Whirlind.

well the stacking gets really crazy though if you are two weapon wielder and have lightning attack..