Thanks to the speed at which Stannis called the banners, Robert and his forces were way ahead of the schedule that they would have been canonically. And he used that to the best of his ability. Robert had ordered the map makers to make maps of all of Westeros, but the maps of the Stormlands were the best ones. And he had memorised all of them. So he knew that Lord Fell would be marching south-west to arrive at Summerhall. Felwood, the seat of House Fell, was located North-west of Storm's End, and because they didn't want to face Robert and the remaining Stormland forces on their own, they wanted to meet up with Lord Cafferen and Grandison at Summerhall.
However, it would never reach that point. When he departed from Storm's End, Robert divided his forces into two hosts.
Westeros was burning with the sparks of rebellion. Gulltown had been taken by the rebels, and Robert had killed Lord Grafton himself. At Storm's End, the mighty stag of the Stormlands had begun his charge, and he wouldn't stop until his antlers were bloody. Thanks to Stannis' swift summoning of the banners, the Stormlands had become a bastion of preparation and had the initiative. Logistics, maps, and war councils had long anticipated this moment, not just Stannis' quick thinking, but also the two brothers' plan to overthrow the Targaryens anyway. So, they had long been ready.
Robert had predicted the rebellion of Lords Fell, Cafferen, and Grandison. These lords, resentful of Robert's rising power and influence over trade and guild reform, wanted to march for Summerhall with plans to combine forces. But Robert and Stannis had other ideas. Summerhall had been rebuilt as a modest guild outpost, a jewel of Baratheon planning and economic revival. What better bait? Compared to what the two Baratheon monsters had cooked up, the three arrogant lords might as well be child's play.
.
Robert's preparations began days before Fell's first scouts moved south. Under the cover of darkness, he positioned his men across the ridgelines and hills around Summerhall. He ordered trenches dug where the ground naturally funnelled cavalry. His siege engineers, whom Stannis and he had trained through years at Storm's End, strung nets camouflaged with leaves and bark across gaps in the terrain. He chose the exact tree lines for hidden archers and even rigged barrels of pitch to be rolled down the slopes at a moment's notice.
He positioned himself where he would be seen, just out of bow range, in front of a false encampment that looked like a disorganised and tired vanguard, quickly assembled and not complete. His men slumped visibly, their banners wilted and untended, campfires small. Smoke rose lazily into the sky. The stage was set. They waited for the man to arrive, enjoying the bountiful provisions they had taken from Storm's End. Such was the advantage Stannis' quick actions gave them.
After roughly 12 hours of waiting, Lord Fell arrived. And he arrived, with over 1'500 men at his back. What he saw was a tantalising target, and he couldn't resist it.
"A spear to the heart and Robert falls," he told his captains. "The Baratheon brat will not even know what hit him."
"My Lord, I am uncertain whether this is such a good idea. This seems too good to be true," one of his men-at-arms told him.
"Nonesense. He has no experience in warfare. Say what you want about his personal strength, but look at him. He thinks arriving early gives him an advantage, but he didn't think about arriving orderly or with enough men. That is a mistake on his part, due to a lack of experience. We attack!"
"As you command, my Lord."
And so, they charged.
.
"Any word from the scouts?" Robert asked.
"Aye," said one of the riders. "Fell's front lines are moving. The formation's thick, confident. They think it's a rout they're charging into."
Robert stood nearby, unmoving, his warhammer resting on the ground beside him. He wore no helm yet, letting the cool morning breeze touch his stern face. He was no longer in a joking mood. This was quite serious. He looked to the east, where the golden light crept down the trees.
"Let them come," he muttered. "Let them think they've won before the first blow is struck. This was the idea in the first place."
Arthur Shelby grinned.
"By the end of the hour, they'll wish they'd bent the knee at the docks and socked your cocks. Hey, that rhymes."
Robert turned to the gathered captains. He looked at them seriously and was ready for war, and he expected them to act the same.
"No quarter to those who refuse surrender. And if Fell lives through the first clash, he's mine."
He donned his helmet, the stag antlers glinting like silver death, and mounted his horse. The captains saluted and then got into positions. Then came the sound of horns, distant but growing louder.
"Positions," Robert said. "And remember, our fists will be louder than their useless cries."
The moment Fell's vanguard reached the tree line, the signal was given. Horns, three sharp blasts, from the western ridge. Barrels of pitch, which Robert had created for construction in Storm's End, tumbled down and burst into flames. Archers emerged from the brush and loosed volleys on the exposed charging knights. And yet, that wasn't all yet. The very earth betrayed Fell's men; horses fell into hidden trenches, snapping legs and sending men flying.
It was terrible for them. Men and horses, flesh and armour, smashed and crashed together, splattering guts and blood all around, killing both animals and humans alike. Hundreds died in this very first charge, and hundreds were hit with flaming arrows or flaming pitch, not understanding what was going on. And then, everything got worse.
Robert and his forces charged.
He was clad in green-coloured steel-lined armour, his eyes glowing with fury. Atop his warhorse, he led a wedge of 400 mounted elite straight into Fell's centre. His warhammer, heavier and longer than most men's swords, swung through the air with earth-shattering force. The first knight to challenge him understood his mistake too late and raised a shield. It was useless. He was thrown ten feet as the hammer exploded against the shield, crushing it. The sheer acceleration Robert could unleash was staggering.
"STORM'S WRATH!" Robert bellowed and crashed through the enemy line like a falling meteor.
He swung his warhammer, dodging slashes of other knights, some of whom were stupid enough. He grabbed a bannerman by the throat and flung him into another one. It wasn't a problem for him, but together with the weight of his armour and warhammer, his horse couldn't take it, so Robert simply jumped off. He trampled over a wounded squire, the earth starting to be a mix of dirt, blood and gore. He used his axe to hook another rider from his saddle, pulling him to the ground. Then, he crushed his chest with a downward strike from his Warhammer and moved on in the same breath.
The Baratheon reserves joined from the flanks. Baratheon and other Stormland soldiers, dressed in armour and wielding quality blades, crashed into Fell's rear ranks, slicing down officers and sabotaging reorganisation.
Lord Fell, desperate and reeling, tried to regroup. He rallied what remained of his household guard near the repurposed Summerhall, wanting to maybe get in and turn this into a siege fight. He was unlucky, though; the strong doors of Summerhall had long been sealed, as per Robert's orders. So, Fell was forced to defend himself, together with the last few hundred of his chaotic and scared forces, against an uncontrollable force that was Robert Baratheon.
After roughly an hour of fighting, Robert found Lord Fell.
He approached him, blood-soaked and breathing as easily as he had in the beginning, never slowing, never tiring. His hammer was red. His armour was a different colour, his gaze fixed.
"Face me!" Lord Fell cried, voice breaking.
Robert didn't speak. He strode forward, and to the surprise of all who observed, disarmed himself. He raised his fists.
That was too much, and so, Fell charged with his sword drawn. He arrived in front of Robert and slashed his blade down, wanting to split Robert. However, the heir to Storm's End caught the blade between his hands, absorbing the blow. He pulled quickly, making Fell, who was gripping the handle strongly, fall off his horse. With one swift movement, Robert then slammed his armoured fist into Fell's jaw.
...
Bones shattered. But the wild man wasn't done. The second punch caved in his cheek, ignoring durability. The third, a brutal and final uppercut, carried enough force to lift Lord Fell off his feet and rip off most of his face. Fell's body landed limp in the mud, turning it into a pool of his remains.
The battlefield went silent.
Robert turned and walked to the few remaining soldiers.
"Do you still want to fight?" he asked.
"N-n-no, m-my Lord..."
"Then get your shit together and get a move on. There's another battle today. And you're my vanguard."
.
By then, the other traitorous lords were approaching from opposite directions. They had heard nothing from Fell, expecting to rendezvous and crush Robert's force with superior numbers; instead, they walked into a war machine already in motion. Another short hour had passed between the end of the fight and the one that was fast approaching. Robert's other part of his host reunited with him after having prepared their own things.
Robert executed what Stannis later called the "Baratheon Crush."
Seeing the results of the initial battlefield, Lord Cafferen and Grandison were surprised, but charged immediately. Feigning weakness in the centre, Robert drew both forces into a narrow killing field where ditches and barricades turned cavalry charges into death traps. The Baratheon army, trained by Robert himself, set off burning arrows as signals and false horns, adding to the chaos.
When Grandison committed his vanguard, Robert unleashed his flanks. The hidden parts of Robert's other part of his host erupted from the woods. The rear guard, hidden beneath camouflage nets, rose like the dead and launched an attack from behind.
Lord Cafferen realised the trap too late as well. He tried to retreat, but Robert had closed every path, mowing them down from the sides and the front, and moving forward fast. Robert led a shock charge through the centre, roaring battle charges with a voice like thunder. He smashed Grandison's guard aside, ripped his axe from his belt, and slammed it through a knight's helm.
A moment later, he dismounted his stallion again, for the very same reason. Any more and he would be wounded. He tore a spear from a fallen man and impaled two others. Then he caught a blade with his gauntlet, yanked the attacker forward, and headbutted him to death. He fought like a demigod among mortals, sweat and blood turning to steam against his armour. His strikes shattered shields and sundered flesh, but they also wore on his Warhammer and waraxe. Action equals reaction after all, and while he made them with better quality steel, they could only take so much.
Grandison attempted to flee. Robert, though, sprinted after him on foot and caught him, dragging the man from his horse. He shattered the Lord's knee with his hammer, forcing him to kneel.
"AAAAAAHHHHHH!!"
"Mistakes hurt, Grandison."
"You think this rebellion is yours to win?" Grandison spat.
Robert grabbed him by the throat.
"It was mine the moment you raised arms against your liege. It was always mine to win. Your pride and feeling of entitlement are what killed you. But you died the moment you planned to go against me, long before today."
*CRACK*
He crushed Grandison's windpipe. Lord Cafferen, still surrounded, attempted one last stand. But his men saw Grandison fall. They heard the rumours that Robert was more beast than man, and morale collapsed. His shield wall faltered. And when Robert turned his gaze upon them, Cafferen fell to his knees and surrendered.
The fighting at Summerhall was over. In one day, Robert had fought against three separate hosts and shattered them with preparation and pure force.
.
The victory at Summerhall shattered any Stormland resistance to Robert's cause. Lord Cafferen's holdings were seized. His household stripped of titles. His name was erased from the ledgers of Baratheon loyalty. The same happened to Lord Fell and his belongings. Robert and Stannis had long planned to dispose of the three Lords in some way and have their lands put to a more beneficial use. That was now possible, as soon as the war ended.
Robert's men roared their praise for him. Stormlords old and young rallied behind him. Even the more hesitant houses, which had joined but were watching from afar, began pledging true fealty towards Robert in their hearts and minds. Now, he was a true Stormlord, worthy of their swords and loyalty.
The rebellion had begun with a surprising bang. With the fight at Summerhall complete and the details written down and sent to Stannis for his information and preparations, Robert Baratheon marched west, toward the Reach, where the loyalists would surely wait with flowers and superior numbers.
However, that was again expected by Robert, and he didn't plan to 'fight' by the book.
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I like to show how the additional time Robert gained was used to fight smarter, rather than harder. The losses on their side were minimal. Battle of Ashford incoming. I hope this was alright. I'm not very good at larger battle scenes.