Now that you’ve persuaded both leaders to head to High Hrothgar, it’s your turn to do the same and make tracks up the mountain. On your arrival at High Hrothgar, Arngeir greets you and tells you to head to the meeting room. He also warns you to expect the discussion to be really rocky- both sides of this conflict <i>really don’t like</I> each other.
When you have a seat at the table, you get to see everyone else who’s present. On the Imperial side you have General Tullius and Legate Rikke, two leaders of the Imperial forces you would expect, as well as Jarl Elisif the Fair, the Jarl of Solitude. She tends to defer to Tullius, much as she does with her ‘advisors’ in her court, so don’t expect her to have much input to give. If Jarl Balgruuf is still in charge of Whiterun, he will also show up on this side, though his personal stance tends to be a bit more neutral and he likely won’t have much to say for most of the meeting.
Also showing up on the Imperial side of the table is Elenwen, one of the heads of the Thalmor observers. Her goals are more complex than the others, and when she gets to have input on the meeting you’re going to have to watch her very carefully- the Thalmor, despite having their agent alongside the Imperials, are decidedly not on the side of -anyone- present, and one of her goals here is to subtly invoke as much conflict and disruption as possible.
On the side of the table opposite you is Arngeir, who presides here to maintain order and keep long-winded diatribes from getting out of hand. Beside him towards the Stormcloaks are Delphine and Esbern. While not terribly respected by the Stormcloaks, these two are at least mostly neutral with the Imperials. Elenwen hates them, however, so keep watch.
Finally you have the Stormcloak side- While the main player here is Ulfric himself, there are two others to pay attention to. Galmar Stone-fist is Ulfric’s housecarl and he has a few bones he’d like to pick with the Imperials- if by ‘pick’ you mean ‘bludgeon into Oblivion and woe betide any who get in the way’. While Ulfric likes to go on rants, Galmar loves to threaten and bluster, and is frequently reined in by his Jarl, though he tends to grate on the Imperial officers. If the Stormcloaks have Whiterun, Jarl Vignar will be here as well. While he has more political opinion than Balgruuf and a stronger tendency towards the Stormcloaks than Balgruuf does to the imperials, he is most interested in keeping Whiterun safe and will largely steer clear of the excesses that seem to take hold of Ulfric and Galmar.
Negotiations begin with a number of long-winded talks from either side and various arguments, but while these vary depending on how things have been going in your Skyrim, there’s really little meat to them. The main importance comes when you start having to make decisions. Pay close attention, because you’re going to want to be very careful how you handle yourself, depending on the kind of result you want.