CON Save is 9, Moonbeam fades when she was hit the first time.

Kess, seeing the attempt to grab at her, moves to somersault over the troll’s titanic grip:

Acrobatics: 22

Kess easily evades the creature's incredibly awkward attempt at a troll hug, and she deftly slips right out from underneath its grasp as she readies for her next attack.

And having artfully dodged it, Kess then decides to follow up her earlier attacks, striking at the giant’s now-vulnerable elbow and underarm:

Moonpetal first: 27

damage: 8

Scimitar second: 17

damage: 6

Chrys points at the second troll, transfering her Hunter's Mark to her next target.

"You coulda jus' moved along, but now yer gonna pay for stayin'," she promises, attempting to attack the troll.  She swings wide, however, as it flails about from Kess's attacks.

Due Process: 11

Lumen also attacks, trying to aim for a side or flank with his sword and dagger.

Longsword Attack: 19 Damage: 11
Offhand dagger Attack: 22 Damage: 2

Watching the first troll fall dead, Lumen turns to the second one, and with a bit of deft bladework, he carves two deep cuts into the monster's side. Streams of dark blood seep from the wound, and the pain causes the troll to twist to the side, just as Chrys swings her hammer. Overextending just a bit, Chrys feels the pull of Due Process slamming into nothing but air, which almost throws her balance off. 

Next to her, Kess leaps into action again and stabs deeply into the creature's rubbery flesh with both of her swords. It seems as if she's finally figured out the balance between the two blades, and she's able to deliver two attacks with near equal strength with both, which bring even more guttural cries of pain and frustration from the troll.

Vesper and Nym are up.

Seeing one of the trolls erupt into flames, Nym nodded at Vesper, feeling a bit less like falling over at the prospect of only one more to deal with. But when she focuses back onto that final one, all she saw was a sharp grasp swing towards Kess and she began to shout a warning, "Loo-!" When the elf deftly summersaulted over the attempt to grasp her in such a movement more fluid than many a dancer, that the woman couldn't help but mumble, "Darkness be damned..." Eyebrows raised in respect. Shaking herself out of her staring, Nym realized that the group had the troll surrounded on three sides and she quickly moved to make it four to try and get a quick jab in with her longsword. 

Attack:  21     Damage:  5

Vesper shoots out a gout of fire at the remaining troll!

13 DC14 for half.

Vesper tosses a Fire Bolt at the remaining troll!

Attack: 25 Damage: 6

Remember, area spells are indiscriminate as to who they target, unless specified. With the other troll, Vesper was effectively fighting on same front as Lumen and Chrys, while Nym and Kess battled the other troll. Now, you're all effectively surrounding the second troll, and since Dragon Breath is an area spell (15' cone), this means you the spell area would also hit your allies as well.

So, maybe you want to do a different action. You can edit if you wish. 

Edited post to change action.

(Is this the first time we've seen Vesper spit flame?)

Following Kess's brutal stabs, Vesper lobs yet another fire bolt at the troll's chest. The creature reels in anger, which gives Nym the opportunity to focus on her own attack. Firmly gripping the hilt of her longsword with both hands, she jabs the blade forward with a quick thrust. The sharp metal sinks almost all the way into the troll's rubbery flesh, before Nym pulls it back with a hard yank. A bucket's worth of blood pours from the wound, which brings an even more vicious roar of pain from the menacing 9' giant. 

Finding itself assaulted by five capable assailants now, one of which is using fire, the troll clearly sees the futility of this fight. Throwing up its long arms and batting away any potential attacks, (Disengage), it backs away from you and begins to flee back into the forest. (30' movement.)

(Yes, I believe that this battle is the first time that Vesper has used her Dragon Breath spell.)

Lumen growls and moves ten feet toward the troll and throws his dagger.

Attack: 8 Damage: 6

Unfortunately, Lumen's aim isn't quite good enough, and his dagger bounces off a tree and skitters to the ground as the troll runs off.

(It is the first time. She only gained access to the spell when we hit 3rd level and this is the first fight where it's warranted using it.)

"Oh, no you don't...! You'll just do this to somebody else, you coward!"

Kess shunts her scimitar into the ground, keeping Moonpetal in left hand as she conjures up and shunts a Fire Bolt of her own into the troll's back.

The fire bolt flies forth: 18
Damage: 5

Regardless, hit or miss, Kessdarra would pick her scimitar back up and give chase as fast as her feet could carry her; she had every intention of finishing off the hulking, stinking giant permanently.

With a similar consequence, Kess quickly shoots forth a fire bolt from her fingers and watches it slam harmlessly into a tree right next to the escaping troll. However, she immediately takes off running after it, sprinting forward with Moonpetal in her hand, dashing as fast as she can through the thick woods and over the uneven terrain beyond your campsite.

Ok, chase time!

Kess, give me 5 d20 CON checks to see how long you can keep up the chase. 

Anyone else can join in as well, or state their actions as Kess dashes after the troll. 

Chrys pulls another javelin and throws it after the retreating troll, before picking up her hammer and joining Kess in the chase.

Javelin attack: 25
Damage: 12 (11 + 1 HM)

Her short legs can only carry her so far, however, as she huffs and puffs to keep up with two.

5 con checks: 15, 23, 12, 23, 15.  Because she has 25 feet of movement, here's a 6th: 8

(Question: Would Vesper need to make Con checks if she's only trying to stay within 120 feet so that she can toss Fire Bolts at it?)