The Dawnguard add-on will be the ideal excuse to dust off your Dragonborn and wade back into Skyrim. But this first slice of downloadable content for Elder Scrolls V, due this summer, has been an enigma wrapped in a riddle surrounded by a mystery and stuffed inside a conundrum. Until now.

Now, the secrets of Dawnguard are secrets no more. The first trailer for the DLC is rich with revelations, and here are the essentials, with rumour-mongering and wishful thinking thrown in for good measure:

1. Vampires, Not Snow Elves

Though speculation initially linked the Dawnguard DLC to Snow Elves, the race that came before the Nords in the land of Skyrim, the trailer reveals it is potentially a lot less about them and a lot more (or entirely) about vampires. Not the sickly blood-drinkers of the main game, but a new fraternity of vampiric badasses.

They have a vampire fortress, they throw a swinging vampire party (corpses on the tables, blood in the kegs), and they feed on fully awake humans that are standing up and everything. No more sneaking around and nibbling on sleeping NPCs for this Dragonborn.

You discover these nightwalkers when you escort their leader's daughter home, in what is most likely the quest that sets you on the path to this new content. They are also a faction with which you can ally yourself. "What is it you seek?" asks Vampire Dad. "Is it to be one of us?"

To which the correct answer is:

2. Yes, Please, I Would Like to Be a Demonic Man-Bat

Throwing in your lot with Team Vampire scores you sweet powers of transformation. In the trailer, a Dragonborn in a circle of blood morphs into a Nosferatu-like, leathery-winged horror. In this beast form, you hover eerily and strike fear into the hearts of your enemies, who are:

3. The Dawnguard, At Last

The titular Dawnguard, then, is a faction of vampire hunters. You can ally yourself with Team Dawnguard but, really, why would you. They might have a fortress, as seen in the trailer, but have no awesome powers of man-bat transfiguration and no ornamental blood fountains. At least they do have:

4. Crossbows!

Though these are most likely available to both sides, since the crossbow is a whole new weapon type--and one of the early Dawnguard rumours that turned out to be on the money. We see a female Nord Dawnguardian firing bolts from one such weapon in the trailer.

How will they handle as compared to conventional bows? GameSpot's staff armourer* advises us crossbows are more powerful than regular bows, but heavier and less precise. So, look out for that, and also for:

5. Mounted Combat!

Finally, you can cut fools from the comfort of your saddle. In the trailer, we see a Dragonborn swinging an axe while trotting along. The word is both ranged and melee combat will be possible on horseback, so you might be firing a crossbow or waving an axe while astride your magnificent:

6. Spectral Horse!

Look upon Dawnguard's spectral mount, ye mighty, and despair. This is a skeletal stallion made of mystical energy wisps. Get out of my dreams and into my Skyrim.

..I'm sorry. I was thinking about spectral ponies. Where were we? Right, yes:

7. New Locations!

Though the trailer does revisit Whiterun and Dragonsreach (with a vampire-induced eclipse looming overhead), Dawnguard also adds new locations to the world of Skyrim. As well as each faction's fortress base, there is a graveyard of sorts under a gloomy purplish sky, possibly accessed via the magic portal staircase glimpsed in the trailer.

After a flash of an Elder Scroll, there's a peek at a map, too: a river runs from the lower left to an ocean or lake in the upper right. The red sigil on the left of the map looks like the horned symbol for the city of Markath. Could the Dawnguard content be centred near there? Could it? We don't know. Hey, look:

8. Capes!

Cloaks, capes, and all kinds of flappy apparel are excitingly confirmed for Dawnguard by the saucy red number on the vampire leader.

There you have it: the Dawnguard essentials, and that's without even dwelling on the frost giant, ice dragon, and vampire transforming into a cloud of bats, as also spotted in the trailer. What else could this first wodge of Skyrim DLC have in store? A certain Electronic Entertainment Expo will reveal all next week.

*Wikipedia