Rell can tell these creatures are in fact, undead. 

Krakk's spear flies true, and meets its mark directly in the back of it's right thigh. It stumbles forward, ending in a half crouch as the spear protruding from it's leg catches in the hard earth. The members of the part on the ground notices that as soon as the spear pierces the dead drow's flesh, the pink iridescent glow fades from it's eyes. Within seconds you start to hear a bone chilling groan emanate from the creature. 

The man with the black hair, and the lighter skinned elf continue to approach the party, unaware of the attack to their companion. They clone in and are within mere feet of Anchor and Rell. Neither seems to make to attack, but the scent of decaying flesh starts to overwhelm both of you. What each of you do?  

Anchor will take his maul and swing at the elf.

Hit: 22

Damage: 13

Finch fires an arrow at the black-haired man.

Attack: 18 Damage: 6

Seeing as everyone moves to engage, Tingting will also shoot her crossbow at the black-haired man.

Attack: 18 Damage: 9

Rell begins to move up alongside Anchor and swing at the elf Attack: 10 Damage: 9

Each of you lands your blow. As Anchor steps forward and brings his mighty maul to bear, he smashes through the chest cavity of the pale skinned elf.
She crumples to the ground, and the smell that explodes from the corpse is unlike anything any of you has smelled before. As soon as the maul makes contact, the pink hue in her eyes fades away, leaving only darkness.

The drow Krakk speared hasn't been able to progress after being impaled, but it's very clearly still alive, scrabbling at the earth with its plum colored fingers.
The man in black takes Finch's arrow to the chest, and at this range the shaft smashes through the rusty plate encasing his torso.

Unlike his companions, his eyes retain their pink glow. The mans mouth opens, but without additional movement the creature speaks in a deep, smooth voice. "I see you've finally arrived. Welcome to Barovia. I await our introduction. Hopefully you'll last longer than this lot."

With that the creature falls silent, and that's when Tingting's arrow tears through the creatures throat. At this the glow in its eyes fades and he too falls to the ground with a clang.

The drow continues to scrabble at the earth, trying desperately to free itself.

Trembling, Tingting drops the crossbow. Gathering herself after a brief moment, she takes out her wand and will try to finish off the drow with an Eldritch Blast.

Attack: 13 Damage: 10

Ghastly white light snaps from Tingting's wand, colliding with the drow. The creature shrieks, then falls still, the acrid stench of burn flesh fills the air.

What do you do?

Rell offers a short prayer for dead, then turns to his compatriots. "Our first order of business is find our way out of this fog, and learn more about this land, Barovia. There must be somewhere safer than these woods." Then, more quietly, he says. "Torm, lend us your strength that we might overcome the ordeals that no doubt await us. For we stand in the midst of an unknown land, in the shadow of a great curse... And so, I pray for your guidance. For your protection."  His prayer completed, The Paladin begins looking around for any signs of a way out of the fog. 

Anchor will grab his gear after hearing Rell "Perhaps we should follow the trail we stand on.  It's possible that it will lead us out, I shall take the vanguard position..." Anchor begins to march forward where the people came from. He will say out loud to the group as he his marching "Don't hesitate, fear can be a powerful tool but it can be harmful too. It's a double edge sword."

"I don't understand, how did we get here? Who spoke to us?" Confused, Tingting will gather her things and follow Anchor.

"How did that dying thing speak?" Krakk asks confused

"Anyway, if you wait here a bit I can fly up to see if there is anything beyond this fog."

After saying this he wait for at leat few of the party to give their "ok" and shoots himself up into the air.

Perception: 20

He then comes back down and tells the party of what he's seen.

"I do not know. But there may be someone who does. I assume that the speaker was someone of considerable magical power, as he seemed to have expected us, perhaps he is even the one who brought us here. I cannot say for sure. Whatever the case, I doubt that this will be the last time we encounter him, judging by his words. As a warning, I sensed a powerful, wicked presence emanating from the west. Whether it was the undead, or something else, I am uncertain."

Krakk soars above the trees, but the fog is so dense, it seems to be without end. If it weren't for the small fire still burning down below, you might have even found yourself lost in the fog.

The fire burns slowly, sitting square in the middle of a clearing. A thin, dirt road leads west. Thick pine trees with low branches line both sides of the road. The road is wide enough that You could likely walk two abreast, although Anchor is large enough that he might have to walk along without a partner by his side.

The road seems to end in the clearing that you find yourself in now.

Finch gathers her belongings and gets dressed and armored.  "Well, let's move, I don't like being near these bodies."

Leading the way Anchor would like to make suggestion "Should we continue or rest here in this clearing? Nothing blocks our view, if enemies decide to ambush us we will see them coming."

"Nothing blocks our view?" Tingting cocks her head in confusion. "You mean except for the creeping fog. No, we should continue on."

As you stand around your smoldering fire, you feel a wet tap on your skin as the sky starts to drizzle down on you. The rain is still light, but the smell of it hangs heavy in the air. It's dark all around, but you think maybe not quite as dark as it had been when you'd first realized you were here. The fog is still thick enough though, that you can't make out the sky.

"We should find shelter as soon as possible."

"Then we should move at a quicken pace if we want to beat the rain fall..." Anchor will suggest we move at a fast pace for travel speed.