(The condition still presumes you know the outcome of the roll, which is not how the ability is written.  Maybe a fairer condition is something like "Portent goes off when an Luckster or ally < X hps is attacked." 

To use it on an advantage situation seems a lot more complicated.  You can surely ensure a potential miss if the first roll is low.  But that's definitely a different condition with some risk of not being effective, e.g. "Use portent on 2nd advantage roll to ensure an ally with < X hps is not hit")

(Advantage doesn't matter.  It replaces the result, not an individual roll.)

(You are right that he wouldn't be able to state that specifically.  I guess his portent just goes off after all.)

(Why? That kinda dampers it, no? Instead of saving you from the crit max damage Inflict Wounds, you are protected from the measly little minimum damage handaxe attack? That kinda lessens the impact it can have.)

(It’s based on the actual description of the ability.  Let me check just to make sure.)

(Actually, it’s even less generous:

”You must choose to do so before the roll, and you can replace a roll in this way only once per turn”)

(It is because you can literally see the future... what’s to say you don’t know that will knock you out if it hits?)

(Oh, I don’t know.  Only the description of the ability.)

(So what's going on and whos turn is it? Can we just make a call and keep moving forward? Considering its my attacks getting screwed I would like to state that I could care less. I expect my actions to be mitigated by magic. I can only hope to wear down caster's resources. If him not getting hit now means I he cant use that shit later I am fine with it. )  

(Description also says that you can do this because you can see what’s gonna happen. It just says you must do it before the roll, not that you don’t knows what’s gonna happen.)

(@Keneux: Agne needs to confirm his position. Then it is the opposing sides turn.)

(Given the fact that this was designed for tabletop play, it is the same thing.  I'm still keeping my original ruling of allowing them not to burn if it if doesn't hit, as it would be useless to go Divination otherwise.)

(Note that this would disallow how Luckster was using it, sorry for the confusion.  Luckster would have taken 7 damage, and blocked the 1 damage axe.)

(Agne, Luckster, Taklakaka and Solsis are up, Agne movement confirmation)

"By the light! That's one big cat!!" He shouts as another undulating mass of star light and ever shifting matter gathers in his hand. The bolt bursts forth of its own volition at Theren again. "Embrace the Light of Creation!" He then moves to J16. 

Attack: (2)26 Damage: 13 at Theren.

Edit for damage type and potential Bounce. 

Not high enough attack roll. Crap Baskets.

Quote from JMBeckwith >>

Agne will step forward through the gate closest until he can see Theren and cast an eldritch blast.

 (If we take this literally, we should just put him just outside the gate at L14 and move on.)

(Still waiting on Agne, Luckster and Taklakaka.)

(Sorry.)

Luckster’s cat Helps Luckster as he tries to break his binds.

16

Succeeding, he moves to 16A.

(Wait, he can’t really help from 10ft away, can he?)

Instead of Helping (still a roll of 15, more then enough), his cat tries to get out himself. 11 but fails.

Tak rages as tries to break the vines currently crushing him.

14 Athletics

 Taklakaka then runs up to 13F

Agne will be outside the gate at L13.

@JMBeckwith Its also your turn. 

(Why did Tak have advantage to escape the vines? There was no help for that check)

(If I recall, he raged. And, it being a Strength Check, not save, he had advantage.)

(So he did, I saw Gad rage but not Tak, though if we don't attack him before his next turn it does end his rage (until he rages again))