Uhm, the not yet decended val'kyrs? if you mean DPS the val'kyr's before the grab people, no you cannot, Here is how they work:
Lich King Yells: Val'Kyr, Your master calls!
3x Val'kyrs appear
They pick up 3 random raid members, The moment they have grabbed a player they can be targeted / DPS'd / Stunned etc, You can do a maximum of 3 stuns on them and they have diminishing returns meaning if the first stun is a paladin hammer of justice (6 second stun), the 2nd stun used on it will be a maximum of 3 seconds, then the third will be a maximum of 1.5 seconds, but the general stunning order is the first stun on all val'kyrs is a big stun, so 6 second stun is done first, then holy wrath (aoe stun for 2s) as the second stun, then again holy wrath is used again as the third stun (1s) so total stun time is 8s. also they need to be slowed and kept at 50% movement speed all the time using various spells from all classes, most have etleast 1 slow that lasts 6 seconds, they need to be kept up Constantly.
If a the raid fails to kill the val'kyr, it will fly off the side of the platform and drop him off of the platform and that's a raid member lost equaling less DPS to kill the next wave of val'kyrs so its critical that all Val'Kyrs are killed not a single raid member can be lost otherwise there won't be enough DPS to kill the next wave of val'kyrs. even if it was a healer that was grabbed by a Va'Kyr and the raid didn't manage to DPS his val'kyr down in time, that is less healing for the raid and most probably will result in a wipe.
Even if the raid manages to kill the val'kyr, it will still return up into the sky to drain the raid's health, this is unavoidable, even if they drop a player or not, the val'kyrs fly up into the air and cast Syphon Life, which constantly drain's the raid's HP untill the end of Phase 2.
hope this helped!
