In The Arts of Dark and Light, Sextus Valerius Corvus has become a successful general because he realizes that proper planning, intelligence and deployment are the keys to winning a campaign, and is good at the same. He isn't useless or a coward in a more direct fight, but his true talent lies in directing larger wars. Corvus also thinks this is true of the younger protagonist Marcus as an officer: though he will never be the greatest warrior in single combat, he is already an excellent tactician, and appears to have the potential to be a great strategist.
Subutai in the Conqueror books; he initially draws attention by helping Khasar and Temuge in a brawl. This draws the attention of Genghis Khan, who decides to reward Subutai helping his brothers by putting him in command of an arban. He comes up with several clever plans during the Mongol attacks on Xi Xia and Chin, and by the time Khwarezm has been taken, he is the second most respected man in the nation. Apparently, Subutai was this in real life, too. By the time the Mongols invaded Europe he was 65 years old and so fat he could no longer ride a horse — so the Mongols loaded him into a cart and carried him to the battlefield because they knew he was worth more than any number of horsemen.
Rincewind. It is attributed to cowardice, but he often shows more sensible tactical thinking than people who actually want to be in a fight and approach it without delicacy.
General Tacticus is described as a great military tactician (in fact, on the Disc, the word "tactic" comes from his name). Later military thinkers from the same region consider this cheating.
In Dragonlance the Golden General Laurana is the brains behind almost all of the Whitestone Council's victories during the War of the Lance. She devises the plans which win the battles at Icewall Castle, and the High Clerist's Tower, after which she is given command of the Whitestone Army and leads it to repeated victories over the numerically superior Dragonarmies, destroying five separate enemy armies and liberating all of northern Solamnia.
The Heroic Legend of Arslan has Narsus, once a chief adviser and tactician under Andragoras, who was removed from office because he was opposed to the kingdom's practice of slavery.
While Honor Harrington initially gains renown as a tactical genius with other Manticoran officers primarily concerned with strategy, when the war against Haven finally ends and Manticore and its allies find themselves facing the massively larger Solarian League, the allied political and military leadership is surprised when Harrington reveals that she had been thinking of the possibility for years and has developed the grand strategy they immediately adopt to survive and win a war with the largest and most powerful entity in human history.
While it's never said outright, this is Gandalf's chief job in The Lord of the Rings. Faced with a world-ending enemy and flanked by allies more eager to do nothing or fight each other. He has to bully, cajole, and charm the remaining free people into forming an effective bulwark against Sauron, and simultaneously give Frodo a chance to get into Mordor and destroy the Ring, and thus Sauron, for good.
August from Of Fear and Faith plays this role when the party defends a fortress from a massive army of Nichts. Between his strategy and North and Phenix's fighting ability, they manage to drive the horde back without any casualties. At least untilFearshows up.
When August is unavailable during the next arc, Aiden fills this role instead and does a good job of it as well. Considering his limited resources compared to what August had available, he might even be better at it.
Annabeth in Percy Jackson and the Olympians and The Heroes of Olympus. The girl's motto is "always, always have a plan". Kind of a given, since she's the daughter of Athena, the goddess of wisdom and battle strategy, y'know.
In The Princess Bride when Inigo and Fezzik are reunited, Inigo wants to find Vizzini and have him plan a way to break into the castle, so that he (Inigo) can kill Count Rugen. However, Vizzini is dead. Then Inigo realizes the Man in Black must have out-thought Vizzini, and "a man who can do that can plan my castle onslaught any day!"
Celeste from Raise Some Hell takes on this role for her group, standing in the back of battles and using her ability to paralyze the demons to make a bunch of small changes that inevitably snowball in her favor.
The Riftwar Cycle: Chumaka lacks the disguise and combat skills of his counterpart Arakasi, being strictly a planner and not a do-er. Nonetheless, he is undeniably brilliant, almost succeeding in setting his master Jiro on the imperial throne, anticipating and thwarting counter-strategies, disrupting large portions of Arakasi's spy network, and only failing in the end because Hokanu of the Shinzawai had learned the truth of his father's assassination, and brought in a force of literal cavalry to avenge it and kill Jiro.
One of the oldest examples is Zhuge Liang, the ancient Chinese adviser from Romance of the Three Kingdoms. He was known as a brilliant statesman and adviser both strategically/tactically and politically, and had a habit of carrying around an elaborate white feather fan — an accessory which has become a popular symbol of The Strategist in many other media. One of his most well-known stunts was Bluffing the Advance Scout — his forces were in a city that was outnumbered 60 to 1 by Sima Yi's incoming army, so Liang ordered the gates thrown open, sitting on top and playing a lute. Because Liang had never bluffed during his military career, the opposing general said Screw This, I'm Outta Here, smelling a (non-existent) ambush.
A Song of Ice and Fire has many military campaigns and strategies but a running theme is that grand strategies run into difficulties, Gambit Pileup, unforeseen circumstances, and that success comes from both grit and luck:
The Posthumous Character, Aegon the Conqueror had three dragons which he used to enlarge and maximize his small army to a force that could take over a continent and it almost worked, except for Dorne. The Dornish used a mix of their climate, the bonds between the Martell lords and locals, and avoided giving battle to the dragons and this allowed them to resist being annexed by the Targaryens for more than 150 years. Then Daeron the Young Dragon using a land-army without dragons achieved the impossible and took over Dorne, invading by land and sea simultaneously and forcing a surrender which might have worked had Daeron worked better to integrate the defeated into his kingdom and not made his conquest resemble an occupation.
Tywin Lannister is a ruthless but very cautious leader who builds his power by means of a Cult of Personality and as a master of diplomacy and subterfuge. While a capable military commander, he has suffered some defeats and setbacks in the past, such as the humiliating raid masterminded by Euron Greyjoy that destroyed the Lannister fleet during the Greyjoy Rebellion, and he is outfoxed by Robb Stark in the field due to initially underestimating Robb Stark because of Robb's youth. He is however a brilliant Opportunistic Bastard who is capable of capitalizing on and maximizing not only House Lannister's advantages, but also even small weaknesses and mistakes made by his enemies, and he brings all the mastery of diplomacy and subterfuge mentioned above to bear in doing so. In the case of the Stark vs Lannister conflict during the War of Five Kings, this means that while Robb is fixated on defeating Tywin through military means, Tywin utilizes his diplomatic and strategic skills to turn disenchanted Stark allies and ambitious underlings against Robb and turn on the Starks, thus handing victory to Tywin on a silver platter despite never having defeated Robb in battle.
Robb Stark is both a brilliant tactician and a strategist. In the early part of the War of the Five Kings, he was cunningly able to outfox Tywin Lannister's strategy and hopes for a quick Curb-Stomp Battle by giving him a feint. Robb then turns around and captures Tywin's son, Jaime Lannister instead, netting a valuable hostage who he can use to negotiate a quick end from a favorable position. This would have worked had King Joffrey not killed Ned Stark, which turned a small war into a longer one, where Robb ends up consistently winning every battle. He once again wrongfoots Tywin by failing to fall into his trap of meeting him at Harrenhal by instead marching west. Most of the time, Robb was able to dictate terms of engagement to Tywin and his campaign came undone because of a single Tragic Mistake on his part: sending Theon Greyjoy to the Iron Islands, and his strategy to undo Tywin came because his subordinate Edmure Tully exceeded his command. However there were numerous other factors that brought him down, such as one of his main commanders Rickard Karstark sending his troops away to hunt for Jaime and another of his main commanders Roose Bolton likely plotting against him from the start.
Stannis Baratheon is considered the best all-around strategist of Westeros. He defended his castle during The Siege in the backstory from a hundred times his numbers, won the largest naval battle in Westerosi history at Fair Isle, and mounted two successful amphibious naval campaigns, against Great Wyk and Dragonstone respectively. Even when he was countered by the equally brilliant Tyrion Lannister once Stannis laid siege on King's Landing at the Battle of the Blackwater, Stannis came very close to victory and breaching the city, smashing the enemy force and putting them to rout in a matter of hours (he did have a 2-1 numerical advantage and better-trained troops, but they had a strong defensive position and magical napalm, yet it was STILL a Curb-Stomp Battle in his favor). He would have easily succeeded had it not been for Tywin Lannister's timely alliance with the Tyrells and his fortuitous proximity to the road leading to King's Landing at the time of his defeat at the hands of Edmure Tully. It's even mentioned that his ships were delayed by the winds, meaning that better winds likely would have enabled him to win. Later, Stannis defeats a wildling army in attack, despite being outnumbered 20-1 (his troops are far better trained and equipped, but the sheer ease with which he wins is impressive nonetheless). Currently he's set to pull victory from the jaws of defeat for his numerically superior but massively outmatched force at the Battle of the Ice, most likely by using an ice lake to his advantage against the enemy's heavy cavalry...
Jon Snow, as a Fake Defector and later, the Lord Commander of the Night's Watch, proves to be quite a brilliant strategist as well. As a Fake Defector, he is able to analyze the strengths and shortcomings of the wildlings in order to defend against their leader's plans to attack the Wall. As Lord Commander, Jon's knowledge of wildling customs and culture allows him to both ally with the wildlings so they can defend against the true enemy — the Others — together, and so he can successfully bring them south of the Wall to save them from this threat. He likewise makes plans to help secure sustenance for everyone being sheltered at the Wall through winter (planning glass gardens, managing to get a crucial loan, etc.), makes every effort to study this undead threat so they can better know how to fight it, and institutes reforms to rebuild and strengthen the Wall's defenses. Jon also gives crucial strategic advice to Stannis Baratheon, outlining an effective approach that saves Stannis from an early defeat and allows him to secure alliances with various Northern clans who can fight in harsh weather conditions, increasing Stannis's strength military strength in his quest to liberate Winterfell from the Boltons.
Strike the Zither: The book focuses on Zephyr, who works as a strategist for Xin Ren. There are also other prominent strategist characters, such as Miasma's strategist Crow and Cicada's strategist November.
The Thrawn Trilogy: Grand Admiral Thrawn from Timothy Zahn's Star WarsExpanded Universe books. He later evolves into a Magnificent Bastard when the Empire crumbles after Endor, when he returns from the Unknown Regions and nearly crushes the New Republic single-handedly. The same trilogy also has the very good strategist Garm Bel Iblis, who left the official Rebellion to fight the Empire with his own group after Bail Organa died and Mon Mothma seemed like she was gathering too much power. Eventually, thanks to Han and Leia's efforts, he joined the New Republic.
Deconstructed in Pfuel, who believes that there is a mathematics to war, a theory that guarantees success if only its postulates are followed. He has no tolerance for any deviations from this mathematics he's envisioned, despite the fact that plenty of other characters with actual war experience know that war isn't that clean. The Austrian general Weyrother thinks he's this, but comically isn't.
Tolstoy had a bit of an ax to grind against officers of German extraction, which also becomes evident in his treatment of Barclay de Tolly (the general and minister of war who had created the Russian army that fought in 1812; he came from the German community of the Baltic provinces of Russia, although, as the name shows, he also had Scottish forbears) and Clausewitz. Also, it is not as if Pfuel (aka Phull) did not have actual war experience, he had served with the Prussian army in wars since the late 1770s.
The first War World book has a story called The Deserter, about a legendary strategist who is being sought by the protagonist because The Empire is losing their desperate war with the Sauron Super Soldiers. But the titular deserter would rather stay and keep his home planet (where his family lives) from fragmenting and balkanizing in the wake of the Empire withdrawing all their troops, so he fakes his own death, with the protagonist's reluctant complicity.
The Zombie Apocalypse novel World War Z features a South African character named Paul Redeker, whose cold-blooded logic got him kicked out the government. When the zombie threat begins to rise, he is dragged back in, and comes up with an effective but brutal method for preserving a nucleus of government.
