Why are there two shouts of the same name and characteristics in the shouts menu? Don't these technically do the same thing? They just have different words and descriptions?

The original Drain Vitality (kill-leech-suffer) "drains health and magicka for 20 seconds".

The new one (stamina-magicka-don't have this one but im guessing its health) "coaxes both magical and mortal energies"

It's a bug we reported and documented well in the Beta. As far as anyone can be sure, it's on the great "fix list". But at least the duplicate doesn't function. It's more or less there for looks. lol

Ahh makes sense now. Appreciate the reply man.

Kill-Leech-Suffer is not drain vitality, its Marked for Death, and it does not dreain health and magicka for 20 seconds. It weakens your opponents armor and health.

No problem, but for future reference if you should happen across any other items that you think are bugs/glitches, feel free to post them in the Hardware and Software Issues sub-Forums in the Skyrim discussion Forums.

That's where the Devs actually cruise to get info on any new issues that may have been reported. Be as specific as possible, and you'll be helping to make this game the best that it can be.

Good looking out though.

The original should be called marked for death and has a different effect from the new drain vitality.

Thats a bug I was unaware of. Didnt happen on my first playthrough of Dawnguard, but good to know for the future.

Yup. It shows up as a second "Drain Vitality", but the words listed for it are the words for "Marked for Death". It doesn't function at all, but it's still not supposed to be there.