(this was preceded by round one, followed by round three)

Rosemary's shout of "GET BACK!" is followed up by a furious series of swings with the heavy paddle at Undead One, but none of them connect with the eerily-gliding corpse.
Undead One attacks Rosemary. The falchion bites deep into the little barbarian.
Rosemary takes 3 slashing damage (reduced by Rage from 7).
On the other side, Undead Two attacks Rosemary, stabbing the dagger into Rosemary.
Rosemary takes 2 piercing damage (reduced by Rage from 4).
Undead Three chooses its target between Arya and Manthis. It focuses on Manthis. The club flicks out and over the warrior's greatsword before he can block it, hitting him between the eyes with a blow that makes his head ring.
Manthis takes 6 bludgeoning damage (4 plus the 2 crit damage).
Undead Four attacks Manthis. Dazed by the blow to his head, Manthis is unable to dodge the stabbing short sword, which plunges up into his armpit.
Manthis takes 7 piercing damage and collapses, dying.
Undead Five attacks Arya, its staff twirling silently in its decaying hands. One ends bats her warhammer aside just enough for the other end to swing around and smack her hard in the side.
Arya takes 3 bludgeoning damage.

The red dot indicates that Manthis is DYING - not dead, but at 0 HP and making death saves on his turn.
Undead Five takes 20 bludgeoning damage and falls inert (destroyed). The air was thick with the stench of decay and blood. One undead had fallen, but at a terrible cost. Arya saw that she and Rosemary were battered and bleeding, and Manthis lay dying. "Run!" Arya shrieked, her voice cracking. "It's hopeless! We have to survive to warn the nearest town!" She bolted, her feet pounding against the earth as she fled past Jonel.
Horrified and in pain with blood pouring from the gash in his chest, Jonel murmurs the words over his cupped hands to cast Fog Cloud. Mist billows out from his hands and envelops the campsite. Unseen, the sorcerer moves away, finding the cliff face by touch and putting his back to it. Everything within the fog is heavily obscured, which means that there is no line of sight and all sight-based attacks in the fog will have DISADV.
@KidEnnui - let me know if I have to position of the cloud right or wrong from what you intended. I will adjust it if it's wrong.

Note that I DID originally place the center in the wrong place; this is the map that shows the correct, intended placement of the Fog Cloud.
20 - Manthis (0/11) DYING
9 - Rosemary (3/13) Raging
9 - Undead One (-16) Two, Three, Four, Five
6 - Arya (7/10)
1 - Jonel (2/7)