So thinking of a Tyrell-Baratheon victory in the Wot5K. I imagine Melisandre, for whatever reason doesn't accompany Stannis to Storm's End, maybe she breaks her leg on Dragonstone or something.
Stannis dies outside the walls of Storm's End as Renly begins to march to King's Landing.
Stannis did manage to inflict losses on Renly, 5,000 to 7,500 Reach and Stormmen died.
Anyway, that doesn't but dent Renly's vast numerical advantage. So Tyrion prepares a doomed defense of the city-seeking to hold the Blackwater Rush as long as possible. While organizing the evacuation of the court to Stokeworth and from there, Harrenhal. However, he can not move fast enough.
A defense of attrition does delay Renly for a time, but the defense can't hold. Tyrion and Cersei die together in the Red Keep, with Cersei showing some surprising bravery of her own. Slaying men at arms with a crossbow and decapitating a man with a sword. Renly had hoped to take the Imp and Queen alive, though neither were too keen on the prospect. Alongside them die Joffrey. Tommen is sent with Balon Swann and Meryn Trant hard to Harrenhall.
As Renly's banner rises in the morning. The city is burned, exhausted and its population starving. The Goldcloaks are basically destroyed as an institution. Shireen is queen on Dragonstone, Selyse having rejected offers of marriage from the Lannisters and Selyse is increasingly under Melisandre's influence, as Mel sees terrible visions in her flames.
Robb Stark ravages the Westerlands and gets as far as within a half day's ride of the rock. However his men are attrited, due to Westermen ambushes in the hills, The Lannisters of Lannisport even placing caltrops on the main roads. So he returns victorious but suffering moderate losses to Riverrun.
Renly now has the Crownlands, Stormlands and Reach behind him. Having caught victory disease, he sends an offer to both Robb and Tywin demanding fealty or destruction by fire and sword(he isn't even interested in letting Robb call himself king-after all he is in a position where it looks like he can impose his will without such concessions).
Obviously both men refuse and the war in the Riverlands grinds to a halt-there is no Lannister-Stark alliance as Renly marches on Harrenhal-Tywin having done everything possible to prepare to defend the giant castle. Tywin and Kevan perish in the siege, with the Lannisters fighting to the last man-Tywin being too proud to surrender, even after it being offered. (Renly liked the notion of Lord Tywin kneeling humiliated before him , and so was willing to offer that). Tommen is ordered sent to the Rock, but disappears en route. He is presumed dead, though in actuality Varys' agents had killed the KG with him and captured the boy-Varys feeling that the false Baratheon child might be useful, "collected" him. (either as lord of the rock or storm's end for Aegon).
Renly's army in the Riverlands basically sucks all the food out of it, even as the BWB conducts numerous guerilla attacks on his massive host. Which by now, has suffered 40-50% losses. Only replaced in spates by Crownlands levies and knights.
Seeing the political opportunity-Robb frees Jaimie, and under threat of death demands he align with the Starks as the Lannister heir-not having much choice, swears allegiance, Jaimie does so-and is sent to rally the remaining Westermen, which are to be placed under Stark authority. Robb feeling this both subordinates and neutralizes the Lannisters, and Catelyn feeling this might give the Kingslayer a chance to redeem his honor. Even so the Westermen are battered and can contribute little. But seeing little choice the weathermen follow Jaimie into vassalage of Stark. Mostly because Renly will likely give their lands to his followers.
LF does work though in getting Lysa to back the Starks, with chaos as his modus operandi-the Vale Knights muster, and ride hard for Riverrun. Renly's forces having just invested the castle. Just as Renly manages to break through the first wall-the Vale comes catching Lord tarly by surprise and smashing the Reachmen and putting Renly to flight.
Renly flees south and licks his wounds.
Now its a struggle between the North-Vale-Riverlands-Westerlands vs the Crownlands-Reach-Stormlands, with Shireen basically a non factor, though Lord Florent does sack up and down Blackwater Bay, and forces Renly to keep a respectable garrison in KL.
Anyway regardless, Renly does manage to gain a victory at Lord Harroway's town, defeating a Vale force(though it was Randyll Tarly who pulled it off). Robb decides the Riverlands are indefensible, even with Vale support and so goes North, with the Ironborn and wildlings having overrun the north, Riverrun eventually falls, though the Blackfish and Stark men continue harassing Renly in the Riverlands. The wildlings and Ironmen though have ravaged the North and Robb seeks to reconquer it. With his core retainers. And the northmen forces available to him there.
With the Vale unable to turn the tide, and Robb focusing on reclaiming the north , Renly is triumphant. Casterly Rock and Dragonstone still hold, to be sure, but not forever. And the Vale Lords will see reason come winter.
Renly is popular with his supporters, though is seen by the Stormlords as being a puppet of his Tyrell friends as they stuff his small council full of them and their own bannermen.
Late in 300 AC, a Targaryen pretender lands in Dorne, with a marriage celebrated under the sound of elephants blowing their trunks and the sound of trumpets. Myrcella is slain by the sand snakes, (there had been some consideration of marrying her to Aegon, though that wasn’t a prospect the Dornish were too keen on). Also Margaery is still without child. As winter sets in...
Some notes-Renly’s host is so massive that he can destroy Stannis, the Lannister’s and Starks in succession
-thus Renly victorious scenarios interest me a great deal.
-Renly is likely is a fairly popular monarch, at least with the noble class, while he is not despised by the peasantry-in fact he is liked superficially, he doesn’t endear himself to them at any deep level and doesn’t really care about them. Beyond PR.
-At the end of the scenario-Renly has both Dragonstone and Casterly Rock under siege. With Jaimie stuck in the Rock trying to prevent its fall. The westermen who remain feeling obligated by oath to die with house Lannister. Though a great many have sworn vassalage to Renly.
Aegon would land in Dorne here. And marry Arianne. Renly being unaware and indifferent, doesn’t keep much an eye on the Dornish, that is until they march out of the Red Mountains.
I suspect Renly would go to meet the Targaryen pretender in the field, surrounded by all the chivalry of Westeros. But he’d face unrest, in the Reach, the Riverlands and Crownlands, and in the West. As many houses declare for Aegon.
I suspect in a battle between them-Connington would prevail. And Renly would either be captured, die, or flee. And thus the Targaryens would march towards a restoration.
Or, maybe the knights of the Reach would win-killing Aegon in the field and ending the Targaryens, until Daenerys came. And she would destroy him.