Monster
All NPCs are referred to as "monsters" in 
The deprecated parameter is being used ( 3.1
). Please remove this parameter from the article's code or replace it with another one. [[Category:Pages using deprecated IILC parameter ( 3.1
)]], 
The deprecated parameter is being used (3.1). Please remove this parameter from the article's code or replace it with another one., and 
The deprecated parameter is being used ( 3.1
). Please remove this parameter from the article's code or replace it with another one. [[Category:Pages using deprecated IILC parameter ( 3.1
)]]. This includes both enemy and allied NPCs. Multiplayer bots are not considered monsters, as they are players.
Important: As a general rule of thumb, monsters are usually only available in single-player mode (deathmatch 0), unless mp_allowmonsters is enabled. This applies to any monster who runs MonsterInit() as part of its spawn function. This notably excludes monsters which are spawned dead, which use MonsterInitDead().Some notable exceptions:
The deprecated parameter is being used ( 3.1
). Please remove this parameter from the article's code or replace it with another one. [[Category:Pages using deprecated IILC parameter ( 3.1
)]] changes most "monster" terminology to "NPC", but some remnants exist, such as the contents flag for NPCs (CONTENTS_MONSTER), and the leftover monster_generic entity. 
Half-Life: Source also retains the monster_ entity classname prefix for backwards compatibility, but uses HL2's "NPC" terminology internally.
Code: Monsters in GoldSrc use the CBaseMonster C++ class, found in basemonster.h.