Forum adverts like this one are shown to any user who is not logged in. Join us by filling out a tiny 3 field form and you will get your own, free, dakka user account which gives a good range of benefits to you: No adverts like this in the forums anymore. Times and dates in your local timezone. Full tracking of what you have read so you can skip to your first unread post, easily see what has changed since you last logged in, and easily see what is new at a glance. Email notifications for threads you want to watch closely. Being a part of the oldest wargaming community on the net. If you are already a member then feel free to login now.

Looking at fielding a few units of Deathmarks with Harbingers of Despair, marking up a few units, and Veil of Darknessing around to hit them with Abyssal Staves that wound on 2+.
However, it looks like the timing of Hunters From Hyperspace may interfere with that if I don't keep them in reserve or set up second, since it says that when they are deployed to choose a unit on the battlefield to be their prey.
If I'm setting up before my opponent and don't keep the 'marks in reserve, do I not get to mark anything since no enemies are on the battlefield yet?

That's how I've always played. If I have to go first, I reserve the unit. (being able to VoD out of reserve is now a pleasant surprise)

If you setup first there are no enemies on the field so their ability goes to waist so if you do have to setup first then reserve them and bring them in with VoD, no point in letting such a nice ability go to waist.