I know there are two different Vampiric Drains--the one you get when you transform into a Vampire Lord and one that's in your Destruction Spells list that you can use when you're not.

Does the one you can use when you're not a Vamp Lord help raise your Destruction ?
And, does using the Bloodstone Chalice give the same buff when you use the Destruction Spell version of Vampiric Drain?

Thanks.

I'm not sure if the Vanilla Vampiric Drain helps your Destruction score, but the buff from the Blood Chalice does affect the Destruction related Vampiric Drain.

All Vampiric abilities and Powers that can be buffed by it, are to my knowledge.

The vanilla vampiric drain is weak and when in vampire lord form with Serana the effect is weakend as well. I have found two mods on Nexus and Steam that I am now runing which makes the vampiric drain a viable spell to use un combat.

I knew about the Serana/Vampiric Drain bug. It's good to know the answer to at least one of my questions.

I'd still like to know about the Destruction thing. I suppose I'll just have to check it out in game...

I don't think it technically counts towards destruction for some reason.

It's a rather useless spell. If it were considered a true destruction spell it could be upgraded, and not be so freaking useless.

But I believe it's strength only goes up through the vampire stages.

No it doesn't increase destruction magic, but it does get stronger the more hungry you are. I do have a mod that increases its stregnth according to the player level so it scales well with the enemies.

Yep the vanilla variant is a bit pants.