Legendary

-Description from Halo: Combat Evolved and Halo 2. -Description from Halo 3.

Legendary is the highest and most difficult setting of gameplay on Halo: Combat Evolved, Halo 2 and, Halo 3. It is symbolized by an Elite's skull with a bullethole of the left side of its head, with two crossed UNSC Standard Issue Combat Knives and the shield bearing the marathon symbol. It is regarded as a challenge for even veteran players, as allies are frequently useless except for diversions, and overwhelming enemy firepower and superior numbers often force one to play cautiously and conservatively. Enemies are extremely strong, while you and your allies' strength are extremely low. The intelligence, enemy accuracy, and enemy numbers are most realistic on Legendary, although strength for all characters is most realistic on Normal. Legendary on Halo 2 can be described as "Trial and Error." Completing the campaign on Legendary in the Halo Trilogy generally unlocks an additional ending to the story.

Legendary was also the name of the highest difficulty setting in Bungie's Myth series, in which it had the following flavor text: "You will brave the army of a commander who has never known defeat, and the piled dead will reach the heavens; but should you succeed, in an age not yet dawned you will be spoken of as a god!"

In Halo: Combat Evolved
In the first Halo game, the differences between Legendary and other settings is relatively numeric. The player does not face unique or different enemies, they just face more enemies who are harder to defeat. Many of the same strategies that work on other settings work on Legendary in this game, except that the player has to be extremely careful of their own weaknesses. This is where the plasma-pistol/human-pistol combo comes in handy.

General differences

 * Master Chief's Shields are half their "Normal" power. A few hits will drain them completely.
 * Enemy shields are double their normal strength.
 * Extremely weakened health meter. One melee from an enemy in front of you will drain 6 health bars.
 * Enemy health meters are double their normal strength.
 * Elites- Twice as many Elites appear as on the "normal" setting. Major Elites are encountered at a ratio of about 1 of every 3 Elites encountered. An area that had two Minor Elites in Normal mode will have 4-5 Elites in Legendary, with 1-2 of them being Majors.
 * Grunts- Twice as many Grunts appear as on the "normal" setting. Around half of the grunts encountered are Major Grunts.
 * Grenades- Enemy Grunts and Elites throw grenades frequently, much faster and almost always accurately.
 * Firing Rate- All enemies fire their weapons much faster and more accurately. In particular, Jackals will fire long streams of 10-15 shots with high accuracy.
 * Agility- All enemies move much faster and will almost never allow a player to stick them with grenades. Elites will often do their dodging maneuver immediately if hit, making it very difficult to consistent hits on them to drain their shields.
 * Stealth Elites are always encountered in packs of 4-6.
 * Flood are now armed 90 percent of the time. Their melee attacks will drain shields by half. Many more of them wield shotguns and rocket launchers than before.
 * Allies- Marines are virtually useless. They will constantly be stuck with grenades, and most are easily killed by the enemy's increased rate of fire, while some only inflict minimal damage on enemies.

Specific differences

 * Pillar of Autumn (Level)
 * The player does not go through the controls section at the beginning of the level, the game assuming that anyone choosing the highest difficulty level has gone through it before. Instead, they will wake up and leave the cryo section immediately.
 * Johnson's speech changes in the begining of the level.
 * Truth and Reconciliation (Level)
 * During the fight in the grav lift room inside the ship, the player and his marine allies will be attacked by 4-6 Zealot Elites wielding Energy Swords.
 * The Silent Cartographer
 * In a difficulty higher than Easy, at the end of the level, there is a Spirit Dropship firing at you.
 * 343 Guilty Spark (Level)
 * The Shotgun is no longer available early on in the game. The only way to pick it up is to kill a Combat Form with one.
 * The Maw (Level)
 * The player only has 5 minutes to get to the Longsword fighter after destroying the engine core, instead of the usual 6 minutes.

In Halo 2
In Frankie's Bungie Updates, Frankie describes Halo 2's Legendary as:

''A whole new sick twist on game difficulty. Legendary includes bizarre stuff like perma-death for co-op players — meaning that you can't hopscotch like you can on other difficulty levels. Once a player dies on Legendary, both players are hurled back to the last checkpoint. It's brutal. Also, that place where you encountered two Grunts and a flowerpot on Normal? Well now they're Hunters, high-ranking, sword-carrying Elites, and they're all PMS-ing. Seriously, sticking your head around a corner on level two can get it shot clean off.''

General differences

 * Enemies fire at a much faster rate and fire far more accurately.
 * Shields are 50% their "Normal" power and a few hits will drain them completely.
 * The Arbiter's active camouflage lasts only five seconds and takes ten seconds to recharge.
 * Enemy Shields and health are almost double their "Normal" power.
 * Virtually every Elite encountered is a Major Elite. Major Grunts are also far more common.
 * Ultra Elites are now common sight, you will encounter up to four in some parts. They have the most powerful shields in the game, and can take four headshots from a Sniper Rifle or Beam Rifle
 * In Halo 2, Elite Zealots now appear as enemies when playing as Master Chief. They always wield swords and will annihilate all the Marines with ease.
 * Enemies are extremely adaptive and intelligent in tactical action. They are very difficult to kill.
 * Grunts retreat less often when a leader is killed.
 * Marine allies are much weaker, but their AI is increased significantly.
 * Melee attacks on you from Elites and Flood are always one-hit kills.
 * Enemies normally have upgraded weapons. For example, Brutes that usually had Brute Plasma Rifles now usually have Carbines and also have the deadly Brute Shot equipped.
 * Enemies will often notice you sooner.
 * Sniper Jackals will appear more often than on any other difficulty. One shot from them will kill you regardless of where it hit, so you should think twice before sticking yourself out into the open.
 * Stealth Elites appear more often, and travel in groups of 2-4, usually with one or two wielding dual-wielded Plasma Rifles, and the others using Energy Swords.
 * Elite Combat Forms will sometimes have Active Camo.
 * Almost all Flood Elites wear shields.
 * Co-op
 * Both players have "linked lives". That is, when one of the players dies, both are sent back to the last checkpoint regardless of whether or not only one of them died (possibly to prevent players from easily reaching the status of beating legendary on their profile, or to enhance it with the general knowledge of the above statement).
 * One shot from Brute Shot will have the same power of a shot of a Rocket Launcher on Easy difficulty.
 * Ironically, for those who finish the entire game on Legendary, there is no secret ending upon completing the campaign, despite the fact that Legendary is considerably much more difficult than the other two games at the same level.

In Halo 3

 * The shield is notably weaker.
 * Enemies are doubled in resistance.

Trivia

 * Every difficulty shield icon has the Marathon symbol on it.
 * Legendary is the top edition of Halo 3.
 * If The Silent Cartographer is played on a level higher then Easy, the Guitar version of the song which plays twice (Opening Cinematic and the bit which you make it up the Silent Cartographer to Echo 419) will play after the transmission with Foe-Hammer after accessing the Cartographer.
 * The Halo 3 Brutes' pack mentality will increase dramatically, thus adding to their already devastating strength in numbers.
 * The second Halo 3 map pack is named the Legendary Map Pack (aptly named, for the previous map pack was the Heroic Map Pack).
 * Many players will use Xbox Live to beat this difficulty; swapping in and out so there isn't a restart from a checkpoint, increasing level runthrough speed.

Related Links

 * Easy
 * Normal
 * Heroic
 * Campaign Complete: Legendary