The Minion Master

A Sub Trope of The Beast Master, a common variety of An Adventurer Is You, and the heroic inversion of the Mook Maker and Enemy Summoner (and occasionally the Evil Overlord). Whereas The Beast Master focuses on quality of minions, often restricting themselves to one or two (or at least one at a time), The Minion Master focuses on sheer, undiluted numbers. This often makes for an unusual and difficult-to-balance character build- a character whose power comes from brutally outnumbering his opponents often leaves himself as the squishiest of Squishy Wizards, and enemies either succumb quickly to the Death of a Thousand Cuts or perform a minion version of a Total Party Wipe with area of effect attacks. They tend, of course, to be the keystone of their Keystone Army.

The key factor in determining if a particular character, class, unit or build is The Minion Master is this: Can the character outnumber a typical squad of Mooks on their own? If the answer is yes, then the character is The Minion Master.

Zerg Rush often describes the most common combat method of The Minion Master. Because of their tactics, they often fall under Anti Hero categorization, and often have to convince the player that Dark Is Not Evil. Can occasionally be Game Breakers, occasionally Crutch Characters. If the minions are copies of the master, it's a Doppleganger Attack.

Action Adventure

 * The Overlord from Overlord is one of these, but he's still a very strong character in his own right once sufficiently powered up.

Fighting Game

 * To a certain extent, Captain Olimar is one of these in Super Smash Bros.
 * King Dedede summons an army of Waddle Dees, Waddle Doos, and Gordos to swarm the stage for his final smash in Super Smash Bros. Brawl.

Hack And Slash

 * Summon-focused Necromancers in Diablo 2 can end up with sixteen skeletons, one golem, and 20 revived monsters. Additionally, you can also hire a mercenary (and should, an act 2 nightmare merc can have Might and increase every minions damage.)
 * Note that, while pre 1.08 Necromancer had far more skeletons, they also became next to useless as the game progressed. Current Necromancers are accompanied by a smaller group of far more efficient undead minions.
 * Necromancers can actually have 20+ skeletons thanks to charms and items granting + to summoning skills. The revived monsters also number in the 40+ zone thanks to this.
 * I've seen a Necromancer that had 35 skeletons, 35 skeletal mages, a golem, and a mercenary. The resulting army covered almost the whole screen. The necromancer was hacked, though, so that every single skill was at level 99. This was in version 1.10, IIRC. But I'm sure it would be possible if someone invested enough points into the right skills.
 * Sacred featured the Vampiress, who could in vampire mode, turn creatures into undead. When she reverted, they died. However, with careful timing the running of the spell on the body could complete after she turned back to normal, which meant that the creature was not subject to destruction until the character changed forms again. What really made it fit the trope though was that the character following could turn enemies into the same state when killed, though not always. Thus a Vampiress could relatively quickly amass a huge army that, because of the way the change worked, potentially turn dragons into undead minions. Such a sight is naturally impressive.

MMORPG

 * Minion Master Necromancer character builds in Guild Wars
 * Currently they can only have a maximum of 10-12 minions at any given time, but they can be replenished very quickly (which is good, because they decay very quickly once they've been around a while). In the past however, there was no limit to how many minions a necromancer could summon and control, you could have massive hordes of 50+ minions if you and your teammates had enough AoE healing to keep that many alive.
 * Also there are the Ritualists, who summon largely stationary but long-ranged Spirits who have a wide range of effects: from dealing damage, to stealing health, to causing blindness, to healing, to taking damage to protect parties, to bringing party members back to life. Of special note is the Ritualist Primary Attribute: Spawning Power, which boosts the stats of created creatures and contains a number of skills that further augment them or benefits the Ritualist when they're summoned. Note that "Created creatures" includes the Necromancer's undead minions, so a Ritualist can dabble in that form of minion mastery too, with mixed results.
 * The 'Mastermind' class in City of Villains. An average Mastermind will end up with 6 minions to boss around, but certain builds can go higher.
 * Controllers initially were allowed to summon as many pets as they wanted to but they would die in about four minutes. With proper recharge and some luck, they could summon up to 20 pets at a time, letting them overwhelm everything. This was nerfed, of course. Now the pets are permanent but you can only summon one set at a time.

Real Time Strategy

 * The Necromancer unit from the Undead faction in War Craft 3. A couple of these guys could summon hordes of skeletons using corpses (obtained from a graveyard, meat wagon, dead unit, or even a dead critter) and Mana. The skeletons were individually weak and short-lived, but the explosive Zerg Rush of that the Necromancers could create, summoning 2 skellies every 8 seconds, could turn a straight battle between initially equal forces into a rout, or at least force the enemy to run away. Thankfully, as of Frozen Throne, mass dispelling abilities were available to all factions, so all it took to clear a skeleton horde was the correct unit (Priest/Wisp/Destroyer/Spirit Walker) and a bit of micro.
 * Some heroes could become The Minion Master using the correct abilities. Like the Death Knight, who could raise 6 short-lived but invincible minions using its ultimate ability, Animate Dead, or the Night Elf Warden, who could summon a minion master, the Avatar of Vengeance, who then spammed further, weaker summons called Spirits of Vengeance. And the Keeper of the Grove, whose Force of Nature ability summoned an extra Treant for every point invested in it after the first. Or the Firelord, whose Lava Spawns would multiply over time if not killed quickly. Or the Dark Ranger, who would turn any unit she killed into a buffed-up skeleton. Yeah, basically, Blizzard loves this trope.
 * Carrier cruisers and carrier capital ships from Sins of a Solar Empire acted as The Minion Master by fighting primarily through their strikecraft wings. They would produce, transport and, in case of capital ships, provide supporting abilities for their strikecraft and fleet in general. The cruiser carriers were, in fact, completely unarmed apart from their strikecraft wings, while capitals would also have some self-defense armament. All capital ships would gain squads as they leveled up, but carrier capitals would, obviously, always field the most squads.
 * You play as a Minion Master in Pikmin and Pikmin 2.
 * The Yuri faction in Red Alert 2: Yuri's Revenge counts by proxy through Mind Control. The Yuri clone can control one enemy unit at a time, the Psychic Tower can control three, the Mastermind can control an infinite number of enemies (but takes damage after four), and both of its Superweapons are designed to take the enemy's units and add them to your own. They also get the Cloning Vats, doubling every trained infantry unit.
 * Carriers in Starcraft can send out up to eight tiny, lightning-quick Interceptor drones each to pepper any enemy that comes near. Every Zerg player counts too.
 * Sacrifice basically makes an RTS of Minion Masters fighting it out.
 * Similarly, Brutal Legend.

Roguelike

 * Summoners in the Roguelike T.o.M.E. Kill an animal, and you can make a totem out of it's corpse. Kill an Explosive Breeder, make a totem out of it, and the children of the summon are friendly towards you - and don't cost you. Filling entire levels with your pets is easy, but considered cheating.
 * The Necromeister in 100 Rogues can summon up to four skeletons and a Shade when the right skills are maxed out. Be warned: it's Cast From Hit Points.

Role Playing Game

 * Focusing on Charm skills in Torchlight can make your character into one of these.
 * This is especially true of the Alchemist if you invest into the Lore skill tree.
 * The player in Fable 2 can be one as well with the Raise Dead spell. At higher levels you can summon six ghosts that are pretty weak but if you've killed a couple of people already these ghosts get stronger.
 * The Summoner class from Hellgate London is this trope. They can maintain one Demon "pet" and any number of elementals which come in 5 flavors as long as they have enough mana for them all.
 * Similarly an Engineer could specialize in one drone, then fill the air with swarms of tiny bots with various abilities.
 * The first Baldurs Gate game didn't have a limit on the number of summoned monsters you could control, so if you happened to get your hands on a Wand of Summon Monster or three, you could overwhelm pretty much anything the game would throw at you. The sequel limited you to five monsters at once.
 * While all three player classes in Geneforge can be this, the Shaper class is best suited for this.

Shoot Em Up

 * The BFT Carrier from Bubble Tanks 2 can summon 6 attack drones that shoot its unlucky victims and burst them in a matter of seconds. It's also rather large and slow.

Turn Based Strategy

 * Marona from Phantom Brave and Zetta from Makai Kingdom are this.

Anime

 * Gecko Moria of One Piece fame has hordes upon hordes of zombies running around on his gigantic island/ship Thriller Bark thanks to the Devil Fruit he ate.
 * Shino Aburame from Naruto is this, letting the bugs that live within his body do most of the work for him.

Card Games

 * One of your options when building a deck in Magic the Gathering is to be fill it with hordes of cheaply-summoned teeny-tiny monsters to overwhelm one's opponent.

Literature

 * The Banned and The Banished adds a touch of Body Horror to this. The first corrupted spellcaster in the series has man-eating spiders living in her womb and gives birth to them when she needs someone dead. Later varieties include a former healer who has leeches living on his flesh, two albino twins who grow pustules that explode into rats, and one villain who's connected to ravens in an unexplained but presumably unpleasant way.

Tabletop Games

 * Most summon spells in Dungeons and Dragons can be used to summon a swarm of lower-level creatures instead of one high-level creature.
 * Dungeons and Dragons also has the hordeificer artificer build that uses the large number of constructs.
 * The Leadership feat causes a group of people to gather around you and mostly do your bidding.
 * The Psionics Revised handbook gives us the Thrallherd prestige class which can easily grant you hundreds of willing minions. Disposable, too, as they'll be replaced if you were to lose any, say, throwing them at a dragon or something. Unlike the Leadership feat, this doesn't cause your remaining minions to have any second thoughts, they're all psychically manipulated anyway. And the class isn't limited to evil alignments!
 * Thankfully Sadly, this has been done away with in 4th ed; while you can conceivably clutter up the room with a zillion summoned monsters, you can only control one of them at a time. Gone are the days of commanding legions of undead, squadrons of angels, and hordes of demons.
 * This editor is uncertain about rules for mass combat in D&D, in which legions of undead etc would act as a single unit under your command. However, one very good reason for the switch was the tendency towards "I attack, then each of my million zombie minions attacks". Aside from the time involved in watching a million zombies attack, it's a bit underwhelming to kill the villain with a Death of a Thousand Cuts like that.
 * Actually, some summoned creatures (like demons) will act on their own if you don't give them any commands, so you can have multiple monsters acting at once. You still can't summon as many of them as in previous editions, though.
 * In Nomine Satanis Magna Veritas, the prequel of In Nomine, allows you to choose lots of human troops that serve and obey you, if you're an angel. The demons get, instead, a lesser demon or some undead troops.

Web Comics

 * Sluggy Freelance's Minion Master is a subversion, since he had no minions until Torg volunteered himself, Sasha, and Bun-bun. And even so, he's been easily manipulated into rubber-stamping Torg's pursuit of his own agenda.
 * Subverted further; it doesn't appear he's pulled as many strings as he's been played himself. His sister may have more control over his organization, but the lunatics have systematically been permitted to run the asylum.