From Quake Wiki
Ogres are the most common foe in the realms of Quake. With a deadly chainsaw for melee fights and a grenade launcher otherwise (though their grenade launcher is weaker than the player's), they can truly pack a punch. If you can, get somewhere higher up than they are, because they are unable to aim upwards and their own grenades might bounce back and hit them. Use a Double-Barrelled Shotgun at close range, 4 shots should put them down. Otherwise, use a Grenade Launcher or a Rocket Launcher for an even return of ammo, as they drop two rockets upon their demise.
The monster_ogre_marksman entity produces a slightly different ogre (won't make a sound when the player is sighted, won't make chainsaw dragging sounds, won't make a proper obituary message, has a different decision-making process when choosing whether to attack, and will in-fight with regular ogres).
"What's worse than a cannibal monster eight feet tall? One with a chainsaw. And a sackful of grenades."
|Monsters from Quake|
|Chthon | Death Knight | Enforcer | Fiend | Grunt | Knight | Ogre | Rotfish | Rottweiler | Scrag | Shambler | Shub-Niggurath | Spawn | Vore | Zombie|