Boss

In video games, a Boss (sometimes called a Guardian) is a particularly large or difficult computer-controlled character that must be defeated at the end of a segment of a game, whether it be for a level, an episode, or the very end of the game itself. Bosses appear in many video games, particularly story or level-based first and third-person shooters, platform video games, RPGs, and most shoot 'em ups.

Bosses in game structure
Many single-player games feature a level/episode structure, the game becoming progressively harder as the player advances. Bosses are a consequence of this structure, appearing at the end of a level or episode and being the hardest enemy to defeat in a given area. Other video games have a storyline instead of a level-based structure, but they still feature boss-like enemies or encounters at various points in the story or at the end of the storyline, some boss fights happen at the front entrance to a level or directly inside the first room, some are fought at middle of the level, while even getting there you may encounter a boss fight.

The boss battle generally marks the climax of a dramatic buildup resulting from the player's anticipation and anxiety. Game designers often add design elements, such as suspenseful music, that enhance this effect. For example, in Metal Gear Solid, the penultimate battle was heavily foreshadowed in the game's dialogue, and the threat represented by the boss was enhanced by an attempt to disable or destroy it before it is even mobile.

A weaker version of a boss that appears earlier in the level is called a miniboss (alternately known as a sub-boss). These are generally intermediate encounters between bosses and standard enemies in their properties. The Hammer Brothers in the Super Mario Bros. game are generally considered minibosses.

Occasionally, a defeated miniboss or boss may return as a standard enemy at a later stage of the game. This typically only applies to bosses or minibosses which are not characters in the game's storyline. For example, in Metroid Prime, the player encounters many Baby Sheegoths before a boss battle against a fully grown one; upon revisiting the level at a later stage, adult Sheegoths are commonplace. In Blood, Cheogh and Shial appear as regular enemies after you kill them. In Duke Nukem 3D, after you defeat the Battlelord, weaker versions of him appear in later levels.

Bosses are traditional choke-points in RPGs, and are used to ensure that the player has taken the time to level-up (raise their abilities and obtain better equipment through fighting anonymous foes or completing mandatory or optional gameplay segments) before progressing to a new section of the game. A player may find that they have not increased in level sufficiently to weather a boss's attacks, and must spend time gaining experience points by fighting lower-tier creatures (often a very repetitive process) before attempting the battle again. This can be viewed as an effort to ensure the player has the level the designer expects before they progress, however it is one of the more common frustrations with the genre.

A boss may also have something the player requires to collect for story progression, like a key, or it may be blocking an entrance that the player needs to progress through. This can often be seen in the survival horror genre of video games.

Characteristics
In complex games (particularly RPGs), bosses are so noted for effective attacks and a large number of hit points. They also have "special" attacks, such as stunning/freezing the player, teleportation, inflicting curses on the characters that decrease their abilities, and so forth. Bosses are often immune to certain abilities that the player possesses, and often can only be defeated by specific attacks and strategies, or by using the environment or their own attacks against them. A common way of implying this power is to make the boss much larger than the player's on-screen representation, as opposed to normal enemies, who are more commonly smaller than the player, or at most roughly equal in size.

In versus fighting video games such as Street Fighter II, the final few characters the player faces in matches are usually referred to as bosses, as they are placed at the end of the game and have noticeably greater difficulty than previous opponents. Bosses in these games are often not available as playable characters at leisure.

In scrolling fighting games and other arcade games, a boss's health level is often determined by a health bar comparatively longer than the player's. When not determined in this manner, however, the character flashes red as he takes hits, progressively flashing faster until he is defeated. This not only determines the boss's health, but also permits internal programming to discreetly adjust it as players enter and leave the game during the boss battle. Sometimes, bosses may also adjust their attacks according to how much damage they are taking.

In more fantasy- or science-fiction oriented FPS games like DOOM or Quake where the player faces different species of monsters, bosses are generally large, highly durable monsters, often with their own unique weapons or special pre-scripted attacks and arenas. In more realistic FPS games where the player faces exclusively human foes, bosses often are unique characters who behave exactly like regular enemies, only with better weapons and more health.

In most adventure video games, there is no real-time combat and thus no boss fights per-se, although the final puzzle often involves defeating the game's main villain, generally utilizing the environment or some previously unused object in your inventory, sometimes under a time limit in which you must act quickly or be killed.

Newer video game bosses some times don't attack at all and just cause many enemies to attack until the player finally kills the boss.

History
The first boss in the history of video games was the Golden Dragon, created by Gary Whisenhunt and Ray Wood in 1974 for Dnd, a game styled around Dungeons & Dragons for the PLATO system. Until this point, games had an infinitely repeating nature (Pong or Asteroids); the boss represented an attempt to legitimize the video game as a type of story, with a difficult opponent ending the game as a denouement or climax.

Early action video game examples include 1980 arcade games such as SNK's Sasuke vs. Commander and SEGA's Samurai.

Criticisms
Bosses have recently begun to fall out of favour with groups of gamers and specific game designers; it is commonly argued that they are a hangover from pay-to-play arcade games, and inappropriate for the current climate of video games. Poorly-engineered bosses may simply be an enemy which absorbs an exasperating amount of damage without providing especially engaging gameplay, existing purely to slow the player's progress. Particularly boss-heavy games may lack coherent segments between its bosses; this is frequently an issue in 2D shooters such as Contra: Hard Corps.

Some gamers have complained that bosses can break the suspension of disbelief by disrupting the level of realism. In games which attempt for a "realistic" atmosphere where the player character and the enemies can survive about as much damage as a "real" human being (albeit perhaps one wearing body armor) could, it can be quite jarring to suddenly encounter an enemy who can survive superhuman amounts of damage. For example, the incongruously drawn-out boss battles at the finales of Half-Life and Halo 2 were derided by many as repetitive, awkward endings to otherwise dramatic, coherent video game experiences.

Alternatively, some view bosses as the ultimate expression of the concepts in the game's design, the other segments bridging and introducing ideas to be explored fully in the boss battles. Developer Treasure constructed Alien Soldier as a relentless series of bosses to interesting effect; the Metal Gear series includes its bosses as the ongoing storyline, battles with them driving the plot ahead; in the Metroid saga, bosses test the player's skill and grant them new abilities which allow the gameplay to expand.

Some notable games which do not include bosses are Half-Life 2, Halo: Combat Evolved, and Thief II: The Metal Age.

Famous or noteworthy bosses

 * Abobo (Double Dragon)
 * Albert Wesker (Resident Evil series)
 * Andrew Ryan (BioShock)
 * Andross (Star Fox series)
 * The Barons of Hell (DOOM series)
 * Big Boss (Metal Gear series)
 * Bowser Koopa (Mario series)
 * Chaos (Final Fantasy)
 * The Cyberdemon (DOOM series)
 * Darth Malak (Star Wars: Knights of the Old Republic)
 * Diablo (Diablo series)
 * Dobkeratops (or Doppelganger, or Gladiator or Krell) (R-Type)
 * Dr. Eggman/Dr. Robotnik (Sonic the Hedgehog series)
 * Dizzy (Guilty Gear series)
 * Dracula (Castlevania series)
 * Ex-Death (Final Fantasy V)
 * Ganon (The Legend of Zelda series)
 * Goro (Mortal Kombat)
 * Great Thing (Darius series)
 * Gunstar Green (Gunstar Heroes)
 * Hustler One (Armored Core series)
 * Icon of Sin (DOOM II: Hell on Earth)
 * Kefka Palazzo (Final Fantasy VI)
 * Lavos (Chrono Trigger)
 * LeChuck (The Secret of Monkey Island)
 * The Makron (Quake II)
 * M. Bison (Street Fighter II)
 * Metal Sonic (Sonic the Hedgehog series)
 * Master-D (Bionic Commando)
 * Mortimer McMire (Commander Keen series)
 * Mother Brain (Metroid series)
 * The Mothership (Gradius)
 * Nihilanth (Half-Life)
 * Nine-Ball (Armored Core)
 * Orstedd (Live a Live)
 * Psycho Mantis (Metal Gear Solid)
 * Purple Tentacle (Day of the Tentacle)
 * Ravel (Planescape: Torment)
 * Ridley and its various incarnations in the Metroid series. He is almost as iconic to the series as the protagonist herself, Samus Aran.
 * Rugal Bernstein (The King of Fighters series)
 * Saren Arterius (Mass Effect)
 * Schwarzgeist (Einhänder)
 * Morganna Mode Gone (.hack)
 * Sephiroth (Final Fantasy VII)
 * Shub-Niggurath (Quake)
 * Sigma (Mega Man X series)
 * Sinistar (Sinistar)
 * Solidus Snake (Metal Gear Solid 2: Sons of Liberty)
 * Ugh Zan III at the end of First Enounter in (Serious Sam)
 * Sorceress Ultimecia (Final Fantasy VIII)
 * Wild Dog (Time Crisis series)
 * Dr. Wily (Mega Man series)
 * The Wizard of Yendor (NetHack)
 * Yu-Yevon (Final Fantasy X)