The third and final game of the Eye of the Beholder series would see players embarking on a quest to the fabled ruins of the city of Myth Drannor. Unlike the previous manuals which described the start of the party's quest with several documents that would entice the player into the world and setting of the game, the third one was notable for the short story, "Moonrise Over Myth Drannor", which was contributed as background material for the game by Ed Greenwood, one of the original designers and authors of the Forgotten Realms series.
The players would be asked to travel to Myth Drannor and reclaim an ancient relic held by a powerful lich before it is used against the world. However, as players would discover, not everything is as it seems, and what may appear to be the end of their quest would only be the start of a desperate fight against a terrible power dwelling even deeper within the ruins.
Eye of the Beholder III (EotB III) was the last in the AD&D based Eye of the Beholder series published by SSI. Whereas the first two, Eye of the Beholder and EotB II: The Legend of Darkmoon, were developed by then Westwood Associates and published by SSI, the last game was developed by a different staff and was remarked upon by fans of the series for the differences within its general gameplay such as its weaker storyline and heavier combat emphasis. Players could import their party from EotB II complete with their weapons, treasure, and experience levels. Given how combat heavy the game is and the general brutality of the first few encounters, this was a welcome option for fans.
Additional improvements were made to the game design as passed down from the previous titles. According to the box text, Eye of the Beholder III boasted:
- Three times more cinematic intermissions
- Five fully-scored music pieces
- Over 70 digitized sound effects
- All-new monster allies
- Outdoor areas
The game was a licensed product of TSR's 2nd edition AD&D rules and used the Forgotten Realms campaign setting as did the previous games. In that setting, Myth Drannor was an ancient city that had collapsed several centuries earlier from the start of the game due to a great evil that had crushed the forces of good there. It was once one of the greatest cities in the world of Faerun and as a result, many adventurers and would-be heroes have been drawn to its ruins in the hopes of recovering some lost artifact or hidden cache of treasure that may still be there. The player and their party are tasked to recover an artifact from the city by defeating the lich Acwellan that has seized it first.
Copy protection took the form of challenge questions that the player would occasionally be asked during the course of the game that would refer to a specific word within the game manual. This was slightly different from the method that was used in the second game as it did not require the player to find a particular picture in order to match the clue to the correct page.
As with the other two games in the trilogy, the manual would continue to be packed with a great deal of information concerning the monsters, classes, and weapons that could be encountered within the game, all adhering to TSR's 2nd Edition AD&D ruleset. New monsters would be described, although as with EotB II's manual, experience tables and other pieces of information were located in the back.
The entire trilogy would continue to use the grid-based, 3D system wherein the world is viewed from a first-person perspective with 90° turns and movement spaces. Within the ever-present interface, a small window on the upper left quadrant of the screen displayed the world as in the first with the party listed on the right. A text box on the bottom part of the screen displayed various messages while a compass was also shown when outside of combat. Random enemy encounters would provide combat opportunities within the game against mixed groups of foes. Everything in the interface was mouse driven.
Party setup and character selection were left entirely up to the player. If the player so chose to create a party of warriors, they could expect extreme difficulty ahead without a mage to help teleport them back home, out of a dungeon, or heal them adequately in combat. A party is limited to six characters, four of which could be created by the player and the other two slots left intentionally open for NPCs that may join later on.
The third game would continue to restrict itself to the initial six races that the previous games had established. As always, the player would be able to pick and choose from each race in order to build the characters they wished and piece together a well balanced party that would reflect their play style. Gender is still a choice although it only affected what character portraits were used to represent each character.
Although the final game had a different developer, it would maintain its use of TSR's 2nd Edition AD&D ruleset, maintaining the restrictions on each race concerning both what classes are available to them such as how far they can advance in certain ones. Racial modifiers can also affect their efficiency in certain professions.The mechanics that the last two titles had used would remain relatively unchanged, allowing veterans to quickly generate their characters if they chose not to import a previous party.
- Human: As in most RPGs, their statistics and abilities are fairly average across the board with no distinctive bonuses.
- Elf: Fair haired, fair skinned, and more agile than humans, their specialties are focused on both magic and war although they tend to do better as spellcasters. They have a bonus to dexterity and the use of bows along with long or short swords. They are highly resistant to charm or sleep spells.
- Dwarf: Short, gruff, and strong, they are renowned for their smithing skills as well as their combat abilities. Being a somewhat non-magical race, they have good resistances against many spells and even poisons.
- Halflings: Short in stature, friendly to a fault, and generally good natured, halflings are also innately resistant to spells. They're also dextrous making them decent fighters and sticky fingered rogues.
- Half Elves: They have no racial modifiers but are somewhat resistant to sleep and charm spells. However, because of their longer lifespans, they are able to multiclass with a greater number of combinations than other races and are decent fighters.
- Gnome: Good as clerics, thieves, and even fighters, they are also fairly magic resistant as their distant cousins, the dwarves, are.
Six classes are available to players to choose from, each with its own set of restrictions. Each classes require certain prime requisites, or ability scores, to be at certain values before that character can become part of that class.
- Fighter: These continue to be the consummate warrior class of the series. They can use magical weapons, rings, but can cast no spells. As they gain levels, they also gain speed which enables them to attack more often in combat. The prime requisite for this class is strength and any race and alignment can be a member.
- Paladin: These are elite fighters dedicated to smiting evil wherever it may be and will not join a party that has evil members. They are immune to disease, have increased resistances to spell effects and poison, and can heal other characters with their "laying on of hands" ability. At higher levels, they are also able to turn undead and can cast certain clerical spells. They also have a persistent aura around them that acts as a negative affect on evil creatures that come too close. Only humans with good scores in both Strength and Charisma can become this class.
- Thieves: A high dexterity is a prime requisite for this class and they are restricted in wearing only leather-type armor and in using a limited number of weapons. Any race can be this class and it is considered an important one to have in the game to avoid getting the party killed whenever a trap is found.
- Rangers: They can use any weapon as a fighter can and can even dual wield melee weapons without any penalty, but only if they are not wearing heavy armor. Humans, elves, and half-elves are the only races that are allowed in the game that can be a part of this class.
- Cleric: They are holy warriors that can fight with a number of weapons and wear armor while casting divine spells against their enemies. Ideal for dealing with the undead as well as healing the party. Wisdom is the prime requisite for this class and any race can be a part of it.
- Mages: The spellcasters of the Realm, what they lack in armor and weapons expertise are made up for in the spells that they can weave. Unlike several other RPG systems of the time that utilized spell points, mages in AD&D have to memorize a set number of spells in order to store and use them at a later time. Once those memorized spells are used up, the mage must take time to memorize another batch. Intelligence is the prime requisite for this class and as they gain in level, they also gain extra slots that can be used to store memorized spells. Humans, Elves, and Half-Elves can become mages in the game.
AD&D along with many other PnP RPGs at the time made extensive use of an alignment system to determine a character's worldview and how they conducted themselves within society which would also be reflected in EotB III's mechanics. As with its previous iterations, it was an aspect of the gameplay that did not actively affect the story in as much as it did in determining who could and could not join the party.
- Lawful: A character will work within the laws
- Neutral: A character will move between valuing a society and valuing an individual.
- Chaotic: A character will choose the good of the individual above that of everything else.
- Good: The character tries to act in a moral and upstanding manner.
- Neutral: A character leans towards evaluating 'situational ethics' depending on the circumstances.
- Evil: A character acts without regard for others or in an overly malignant manner.
For example, a Lawful Good character would be by-the-book when it came to upholding the good in society while a Chaotic Good character would be more willing to bend the rules in order to provide the same. A Lawful Evil character might hold their word as their bond and be loathe to break it for anyone, but would only give it if confronted by someone whose power they respect or as a part of one of their fell schemes. As interesting as this was, the game did not make an extensive use of the potential that this system could bring to an RPG.
Character attributes would help determine what classes were available for certain characters and how well they would perform in them. In 2nd Edition AD&D, attribute scores of 18 were considered the highest possible in a natural sense, although racial bonuses and magical effects/enhancements in the form of spells or items would be able to raise them higher either temporarily or permanently in more rare cases. These are set as far as the game was concerned. Leveling improved a character's HP (hit points) and general abilities, but their base statistics would almost never change.
- Strength: This determines the amount of physical damage that a character can inflict. With a strength statistic of 18, an additional variable is added to indicate exceptional strength as a percentage shown as 18/23.
- Constitution: A character's health and toughness is determined by this. In AD&D, this has other effects outside of simply determining the HP amount gained after every level, such as a character's resistance to certain physical effects.
- Intelligence: A vital attribute for mages as they learn spells.
- Dexterity: Characters with a high dexterity tend to be nimble and agile improving their AC (armor class) which measures how hard they are to hit in combat. Important for every class, but moreso with others such as fighters and thieves. With a score of 16 or higher, fighters can negate some of the penalties levied against them for using dual weapons.
- Charisma: This determines how attractive or repulsive a character is to everyone around them, whether it is in how they carry themselves in conversation or appear in public. Important for paladins.
- Wisdom: A character's innate ability to judge situations and make the best choices. It is also important in spell resistance and particularly key for clerics. Higher wisdom scores above 13 also translate into extra spells that clerics can utilize.
The combat system remained relatively unchanged from the previous titles, although it would occur with a noticeable increase in frequency which would be criticized by players at the time of its release and be one of the major differences between this and the presumed nadir of the series, Eye of the Beholder II. The mechanics would continue to be familiar to veterans while the learning curve was made more difficult with the number of random encounters that would be found in this last chapter of the series.
Fighting in the game continued to be handled through random encounters wherein experience, items, and gold are earned. The front ranks, determined by the two characters at the top of the party list, can engage in melee combat. All other characters must resort to ranged weapons or spells in order to join in the fight.
Camping was available for the player to rest and heal the party, memorize spells, and save the game when necessary.