When we started designing the hostile NPC encounters for The Chronicles of Spellborn (TCoS), we worked towards a system that mimics real live hostile behavior as much as possible. We didn't want to just 'randomly' place mobs on the maps that would simply react to agro and start their melee routine or throw some fireballs. In order to achieve this goal and still be able to populate the massive world that is required for a MMO, we broke each NPC encounter down in 5 components that together define the behavior of hostile NPCs.
As a game designer I can tweak these 5 components to define unique encounters with relative ease. To better understand the impact of each of the components I will give a run down on all of them.
Faction
TCoS has many different factions. All of these factions have a specific place and role within the world and its history. Seeing as all these factions have different backgrounds, making them all fight the same would result in a monotonous and unrealistic stream of enemies from level 1 to 50 (and beyond). It's this monotony we want to avoid with our approach to engaging combat.
A good example is the difference between the Howler and Arionite factions.
Howlers are a very driven alien-like race that, when they have their enemy in sight, will stop at nothing to annihilate that enemy. Although they lack a certain individual intelligence they are all well aware of the presence of their hive members. This results in the Howlers having a wide range of swarming tactics. They try to defeat the players with numbers. Although, when push comes to shove, the Howlers can field very strong opponents that will defend the hive to the death.
Arionites have a basic military history and hierarchy. This has resulted in the Arionites 'thinking' more about their strategy and attacks then the Howlers. Arionite groups are often more intricate in makeup. They consist of units that work well together and will also try to execute their attack with this compatibility in mind.
By tweaking the faction settings the relative intelligence of a NPC group is simulated so certain factions will for instance have stronger units near camps and scout units patrolling the camp's outskirts.
Group
When the faction is defined I can set the parameters for the encounters group definitions. Not all encounters will feature the same amount of units for each encounter. Mostly based on the purpose and the location of the encounter, the number of group members is defined. Although TCoS will feature single unit encounters, a lot of the encounters are strategically placed groups that require a group of players and some good tactics to defeat.
With TCoS we took some bold steps towards agro management. When a group of players attacks or gets attacked by a group of NPCs, players get assigned an NPC to fight with. No longer will the tank just stand in the middle with some casters and healing giving support. The assigning of 'sparing partners' is based on 2 things being the NPC's class and the NPC's attack pattern. Let's look at the class component first.
Class
When the faction and group parameters are set, the classes can be defined for each unit in the group. Based on the chosen faction a list of classes available to that faction is generated. Each class is based on the roles listed below.
Each class can have one specific role or a combination of several of these roles. For example an Arionite scout is a light melee, alerter unit while the howler orb is a heavy melee, healer unit. These roles, we call skill types, these skill types determine what skills the units will have in their skill deck. This is the same system that is available to player characters including rotating tiers of skills.
When the classes are defined for each unit in the encounter, each unit gets assigned an attack pattern.
Attack patterns
Attack patterns are used to define the attack style of each unit. Although 2 units within a group are for instance defined as a fighter class, it doesn't mean that both of these units should act exactly the same.
Attack patterns can be compared to plays in American football where every unit (football player) has its own specific role to play and route to take. Attack patterns determine which target a specific unit will choose and what action the unit will take against that specific target.
With each unit in an encounter given its class and attack pattern the level parameters come into play.
Level
Based on the deployment location and, to a lesser extent, the purpose of the encounter, the level parameters are set. Each unit gets assigned a character level defining the unit's statistics such as hit points and resistances. The system creates it's own small level range variations within the level parameters to create subtle differences between units that get assigned the same level.
To further enhance the uniqueness of an encounter, each unit can be assigned additional Personal experience Points (PeP) ranks. These PeP ranks give the unit bonuses to their basic statistics. This way a group can be created with units that are extra tough for their level or a group can contain a stronger 'named' unit.
Wrapping this up, I can assure you that we worked hard at creating unique hostile encounters in a unique world. Of course TCoS wouldn't be the MMO it is if we didn't have some additional encounters to be found. For the boss monsters we used extensive scripting to create encounters that require some serious thinking and effort. But those will stay hidden for now…
