Preexisting Encounters

In addition to Random Encounters, in which a fight can happen at any time, either in a dungeon-type area, or on the overworld, Preexisting Encounters are those that you can see coming. This tends to happen in one of two ways:

The fight is a mandatory (often plot-dictated) event occurring at this point in the level or game design—which, as a rule, includes most Boss Battles.
Enemies which are visible on the overworld, and the battle doesn't begin unless (or until) you come into close contact or proximity to them. You may or may not be able to go around them and avoid a battle entirely, but you at least have the advantage of spotting them from a distance and having time to prepare for battle.

It should be noted that many games have a mix of two or more of the encounter styles, depending on the area you're in. See Roaming Enemy for when the gap between this and Random Encounters is bridged somewhat. Also, see Inescapable Ambush and Teleporting Keycard Squad.

Examples of Preexisting Encounters include:

Set Encounters

Action Adventure

Zelda II the Adventure of Link has certain squares on the overworld map that lead to a monster battle when stepped on, no matter what. There's a particularly annoying series of them near Death Mountain that you need to pass in order to reach the last part of the game.
- If your timing is just right, you can lure an enemy onto those squares and get off with a much easier encounter.
Okami has several of these. A lot of them introduce a new enemy. They return in Okamiden, where they're visible.
In the side-scrolling Action RPG Zombie Hunter, each stage consists of a series of predetermined enemy battles.

Role-Playing Game

Numerous trainers in the Pokémon games are entirely avoidable, and legendary Pokémon (except for the free roaming kinds) appear as sprites on the screen that the player has to walk up to to initiate the fight, and most can be ignored completely. However, starting with Ruby and Sapphire, if the Pokémon on the box is legendary, the one pictured almost always must be encountered (the only exception so far is Emerald, the Updated Rerelease of that pair of games, since the mascot, Rayquaza, only needs to be approached instead of fought; a battle with it can optionally be done later). The only games not to have a legendary Pokémon on the box since then were FireRed and LeafGreen, which have the same mascots as the original Red and Green, though when Gold and Silver, the first games in the series to have legendary mascots, were remade as HeartGold and SoulSilver, the remakes changed it so the mascots had to be encountered before the player could go for the Pokémon League.
Chrono Trigger (and its successor Chrono Cross) often gave the player the option to avoid fights if they wished. Sometimes, though, monsters jump out from out of nowhere and ambush the party in pre-determined locations, and other times they are visible but unavoidable. Interestingly, Chrono Trigger didn't transition to a separate screen for battles; instead, when enemies attack the Player Characters, the battle menu pops up on the same screen as when they are walking around (Chrono Cross, however, does not do this).
- Treasure Hunter G works in exactly the same way.
Code Lyoko: Fall of X.A.N.A.: Nearly every single battle is unavoidable because the monsters don't move on the field until the player (whose character is a "Sooper Deformed" variation of one of the Lyoko Warriors from the series) enters a monster's detection area, which is guaranteed to cover the whole width of the path that you must go to the target of a mission, usually a Tower or a certain teleporter. As soon as you enter the field, the monster moves to you (surprisingly, except for Megatanks, but battle still ensues when triggered) and you enter the battle. The only skippable monsters usually guard alternate paths (which almost always lead to item-containing Data Packs, some of which contain vital Plug-ins (equippable items that require points to activate, similar to Badges in Paper Mario, except that point upgrades are automatic) or powerful items). Most battles can be seen coming, except for certain boss battles, where the boss hides offscreen until the battle is triggered. And all battles in this game are RPG-style, rather than the action-based battles of the first two games.
A good number of the fights in Crisis Core: Final Fantasy VII are like this. The first dungeon uses them almost exclusively. The one battle required to complete a side mission in Crisis Core is this as well. All other battles give the impression of being Random Encounters, although they only trigger at specific locations due to the realtime nature of the game's battles and can often be avoided by hugging the walls.
Due to the linear design of Dungeon Siege, which forces you to take one route from the beginning to the end of the game, all encounters are set. Avoiding them is virtually impossible, unless they are nestled in a "side-area" which can be skipped. And due to the bird's eye view 3D gameplay, you can always see what's coming up, and it is often necessary to prepare your attack and wear the proper gear before charging in. This is subverted in some areas (like going down an elevator) and in Dungeon Siege 2 (where enemies sometimes pop out of nowhere), but the vast majority of encounters are not surprising and not avoidable.
Dragon Age: Origins uses this, for good reason. Enemies scale with your party's average level, and since stat do have caps in that game, grinding to level 99 makes all of the enemies nigh impossible to defeat since theirs don't.
Magi Nation goes in and out of this trope. in Shadow Geysers and the Shadow Hold, they're completely random - but in everywhere else, they're entirely skippable.
You can't see them in Final Fantasy I, but there are squares where you are guaranteed to get into a battle if you step on them. These are almost always squares adjacent to treasure chests.
- Final Fantasy IV has three set encounters with a Behemoth on one-square-wide paths in Bahamut's lair. Unlike the set FF1 encounters though, these disappear once you've won them once.
In all Chinese Paladin games the monsters are physically represented on the map patrolling the areas. However, sometimes their sprites are tiny and blends in with the background, making it harder to see them coming. Regardless they all will chase the player, usually at a faster-than-walk pace, after they've seen you.

Skippable Encounters

Action Adventure

With the exception of the situations mentioned under "Set Encounters", the standard for battles in Zelda II: The Adventure of Link is that, while walking off-road, enemy sprites will appear and move about the map, and if you can avoid them then you won't go to the battle screen. They can also be skipped to an extent by walking onto the nearest road, because running into an enemy sprite on a road results in the battle screen that appears there not having any enemies, after which Link can easily walk away and continue exploring the overworld.
The Harry Potter games for Game Boy Color. Enemies are represented as small sparkling blue clouds, while bosses are shown as larger versions of the same. You can avoid most random encounters, but bosses typically block progress until defeated.
Okami has Demon Scrolls, which trigger an encounter when they touch you. They follow you around and can be stunned with a brush stroke. There's also Devil Gates, which you have to go out of your way to trigger the encounter. Some of the Devil Gates can be brutal. Demon Scrolls return in Okamiden.

Role-Playing Game

SaGa Frontier displays monsters on the screen as location and enemy-type relevant sprites. In many areas, it's possible to just walk around them.
The SaGa 2 and SaGa 3 DS remakes replace Random Encounters from the originals to monsters running on the world map representing battles. Most are possible to avoid.
While the original Lunar used Random Encounters, the remake displayed the enemies as monsters, making battles potentially avoidable.
Dragon Quest IX has some, different for the series. However, similar to Super Mario RPG, one enemy on the screen represented a party, or a single monster. This made hunting those elusive Metal Slime a lot easier, at least until the Tower of Nod where the King metal slimes hid in groups. However, on the downside, they chased you, which certainly didn't make it any easier to avoid them. (And later on, you ran into enemies who block your way)
In Kingdom Hearts Chain of Memories, the only game in the series which separates the battle screen from the exploration screen, you could skip random Mook encounters. Whenever they touched you, you initiated combat with them. However, if you struck them first, then they begun the battle stunned. (And, if you used the right card to form the room, pre-damaged) You could avoid them as much as possible, although if you used the right card to form the room, they would chase you.
In the Grandia series, not only are the enemies visible, but how you make contact with them effects whether you get first strike or not.
Super Mario RPG: Legend of the Seven Stars has enemies walking around, but like the PC a single enemy represents the whole party.
- Paper Mario games has the monsters walk around in plain sight, with contact leading to combat. They can be avoided entirely, or the player can opt for a First Strike (leading to a bit of extra damage) by jumping on the enemy or hitting them with the hammer or certain partner skills. Some badges also provided other options. One of them would instantly defeat weak enemies if you hit them on the field, while another would stun the first enemy instead of damaging it.
- Mario & Luigi games have this as well. If an enemy hits the second character, they get the First Strike.
- Super Mario Bros 3 has the Hammer Bros., Boomerang Bros., Fire Bros. and Sledge Bros. randomly wandering around the world maps. Mario is transported to a battle screen if they run into him, but can sometimes avoid them.
In Persona 3 and Persona 4, Shadows walk the map as blobs - black blobs are normal, red blobs are Elite Mooks, and gold blobs are Metal Slime. Hitting them with your weapon starts the fight. Hit it in the back and you get a surprise round; get hit first and they get the first move. If you level up enough, they run from you - and if you happen to fight them anyway, the enemies will suffer from the Distress status effect.
Unlike Xenogears, the Xenosaga game series is composed entirely of non-random encounters.
In The World Ends With You, you fight Noise by scanning your surroundings with the Player Pin and then touching those red monstrous-looking symbols to begin battle. In essence, battles that don't advance the story or clear out invisible walls are completely optional, though you miss out on pins, EXP, and PP if you decide not to battle a lot. This can make things very difficult later; even on easy mode, the final boss essentially becomes a Hopeless Boss Fight.
- However, you latter run into a type of Noise that head towards you whenever you use the Player Pin (which you also can't run from), and near the end you'll have a chance of being forced into a battle whenever you got to a new area.
The fifth game in the Breath of Fire series, Dragon Quarter, got rid of random encounters and had the enemies appear on screen. It distinguished itself from other games that do this by encouraging you to use bait and traps to lure the enemies into better positions for you to attack them.
In The Elder Scrolls IV: Oblivion; enemies may be concealed by terrain or vegetation, but often can be seen at a distance, and indeed may not see the character, giving the player the chance for a missile attack or just to flee undetected.
- This also holds true for The Elder Scrolls III: Morrowind, though the sheer number of Cliff Racers you face can make it seem like you're fighting random encounters every step.
Unlike the rest of the series, in Final Fantasy Mystic Quest. The monsters in the dungeons are always visible and in fixed positions. There are two exceptions, but there are items to counteract their invisibility (which, conveniently, are found in that very same dungeon). Luckily for you, they don't respawn until after you leave.
Final Fantasy XII has something like this as well, although you can't always avoid the enemies. Some of them come after you. On the other hand, some of them won't attack you until you attack them first.
Final Fantasy XIII has visible encounters as well. Some enemies completely block your path and you are forced to fight them. Preemptive strikes occur when you approach the enemy from behind without alerting them.
In EarthBound, not only are enemies shown clearly on screen, but the direction your character is facing when the encounter occurs makes a difference. If the enemy is facing away from you, you get an additional turn at the start; if you're facing away from it, the enemy gets the first turn. If an enemy was weak enough that you could kill it before it got a chance to attack, it was defeated instantly. Getting an extra turn at the start of battle made this much more likely.
- Also, very small enemies—such as ants and slugs—who are actually quite tough will be squashed underfoot unless another enemy attacks you while you're immobilized.
- Mother 3 has a similar system, although back attacks never lead to automatic victory; instead, if you are on a high enough level, you can just dash through the enemies, gaining no rewards but also avoiding the encounters entirely.
Dragon Quest VIII, in addition to its normal random encounters, also has some monsters for the Monster Arena visible on the world map. While they give chase if you are near by, they can usually be seen for some distance off, and can be avoided.
The Valkyrie Profile games have enemies visible onscreen as shadowy shapes similar to Persona 3's blobs. These can be frozen and used as steps.
- The third game, being a Strategy RPG, has Set Encounters rather than Skippable. There's only a certain amount of story battles total, with a handful of optional fights scattered throughout.
Lufia II has enemies visible on the screen in dungeons, allowing you to avoid them if you wish. You can also stun them with arrows to dart past them with ease. Some of the enemies move in unusual set patterns, others can teleport around the room, and some puzzles even require you to lure monsters onto switches. There's even one puzzle that has you bet on which monster will win a race!
Mana Khemia: Alchemists of Al-Revis shows enemies as blobs of varying shapes, sizes and colors, depending on their power relative to your party.
Later games in the Tales (series).
In Mega Man Battle Network 5, there are image data of some Navis on some places on the Net. The player could freely fight the image data any time they wanted to.
- In all the games, V2/Alpha boss rematches are invisible encounters set at specific points on the overworld, usually on a random dead end. You can actually tell when you have it right - Mega Man will return to his standing position right before the Fight Woosh rather than freeze in the middle of a step.
Valhalla Knights 2 lets you see the enemies wandering around the dungeon, and if you can get around them you can even start the battle with the advantage of a back- or side-attack. Of course, if they spot you and give chase, they can do the same thing to you.
Guardian's Crusade uses this, with enemy encounters represented as white ghost/tadpole-like things on the map. In addition, the ghost's appearance and behaviour denoted the kind of battle it would be - an easy battle with a weak enemy would be represent by a small, blue-eyed ghost that ran away from you, whereas a stronger enemy would be larger, have red eyes and actively come after you. The in-between ghosts had green eyes and just sort of wandered around.
Robotrek on the SNES has normal enemies usually meandering around the environment. If they see the player they will usually speed up and give chase. Any time the enemies touch the player's sides or back, they get the first move in battle. Though there are also a handful of mandatory, non-boss encounters.
Blue Dragon has enemies walking around most areas. Outside of encounters, you can attack them from behind, get the first attack on them, and use certain class skills within a fixed radius to attract, repel, stun, or sneak past them outside of battle. You can also fight them in consecutive battles, or even pit some of them against each other this way.
In Septerra Core: Legacy of the Ancients, every battle is a set encounter. Worse, if you leave the map and have to backtrack later, every encounter is respawned in the exact same location. Some battles are skippable only if there's multiple ways to get to the destination, and even then, there's almost always at least one encounter on each route.
Final Fantasy Crystal Chronicles: The Crystal Bearers are not only preexisting, but limited. Almost all of them are avoidable.
In Project .hack and .hack Conglomerate games (that is, first four Infection, Mutation, Outbreak, and Quarantine games and the GU games), all encounters are never random and can be seen clearly, though GU is less random than Infection, Mutation, Outbreak, and Quarantine. In Infection, Mutation, Outbreak, and Quarantine, enemies are represented by glyphs and while monsters correspond to area levels and keyword, it is still quite a surprise. In GU, all enemies are out in plain sight, going on a pre-existing path. Whether or not you want to engage or skip it is entirely your choice...to an extent. The way the Areas are mapped, usually consisting separate "islands" or "rooms" connected by paths, you may or may not be able to avoid enemies from seeing you and hence avoid battle (except for the wide open Infection, Mutation, Outbreak, and Quarantine Fields).
The Legend Of Heroes games, recently remade for PSP, have their "random" encounters wandering around the overworld. They'll home in on you at close range, but if you're careful, you can pretty much avoid them completely.
In The Magic Candle, enemy parties are visible to you when they're one tile away. You're visible to them at two tiles' distance, and unless they're holding a position, they'll come after you. A Nitro Boost will keep you ahead of them... but may crash you right into another party. It's safer to use magic: the Locate spell will make all troops visible for a few turns, and Confuse will shake off a party that's caught your scent. (Later, the Teleport spell makes Locate obsolete—you can't 'port right into an enemy party, so you can check where they are by preparing Teleport, noticing the conspicuous unavailable tiles, and then cancelling.)
Eternal Sonata
Parasite Eve 2 uses both types. Some rooms may look clear but the minute you explore a certain part, you are ambushed no matter how much you try to get around it. For the most part, you can see enemies on the field and if you are sneaky enough, you can walk by them without triggering a battle.
The Citadel in Wasteland is filled with dozens of monks and nuns, and every one has a unique name. Consequently, although it's one of the most dangerous places in the game, it's also one of the only ones without random spawns.
All normal enemy encounters in Dubloon are represented as figures walking mindlessly around, with a sprite representing the "leader".
Freelancer has encounters set as 'Patrol Paths' which can be from any faction, although the factions they belong to are easy to deduce because of location and whether they're neutral, friendly or hostile.
Every single non-essential encounter In Star Ocean: Till the End of Time. Also, they are all Actually Four Mooks.
SD Snatcher shows enemies moving around on the screen.