The largest group of all. They're probably the most devastating, from Hiddens to Advocates. Beware when you face Demons, and be sure that you use the right kind of ammunition.

Hiddens warp in and out of your sight. When invisible, you can still hit a Hidden (bows, spells recommended) by holding down the shift n left-klikin the area around you.

Hidden Type
Resistance
Immunity
HP
Damage
Hidden none none 4-12 3-6
Stalker none none 15-22 8-16
Unseen magic none 17-25 12-10
Illusion Weaver magic, fire none 40-60 16-24

You may encounter Goat Demons on the last level of the Labyrinth or the Catacombs. These demons attack you in numbers, and their archers possess incredible accuracy. Take them out as soon as possible, with any means.. or you're gonna get hurt.

Goat Demon Type
Resistance
Immunity
HP
Damage
Flesh Clan (Mace) none none 15-22 4-10
Stone Clan (Mace) magic none 20-27 6-12
Fire Clan (Mace) fire none 25-32 8-16
Night Clan (Mace) magic none 27-35 10-20
Flesh Clan (Bow) none none 10-17 1-7
Stone Clan (Bow) magic none 15-20 2-9
Fire Clan (Bow) fire none 20-25 3-11
Night Clan (Bow) magic none 25-32 4-13

Overlords are huge, slow but powerful demons that attack with brute force. Later in the dungeon you will face the Butcher, who is an Overlord himself. Becareful when fightning Overlords.. range attack is most advised.

Overlord Type
Resistance
Immunity
HP
Damage
Overlord none none 30-40 6-12
Mud Man none none 50-62 8-16
Toad Demon none  magic 67-80 8-16
Flayed One magic fire 80-100 10-20

Magma Demons propel balls of molten lava to your direction in quick succession. Dodge these projectiles as much as you can, for they can inflict alot of damage.

Magma Demon Type
Resistance
Immunity
HP
Damage
Magma Demon none fire, magic 50-70 2-10
Blood Stone none fire, magic 55-75 2-12
Hell Stone none fire, magic 30-40 2-20
Lava Lord none fire, magic 35-47 4-24

The first lightning based attacker you will meet is the Red Storm. This foe is though, and can spray an area with lightning in seconds. Get lightning resistance as soon as possible, or you're gonna be fried.

Red Storm Type
Resistance
Immunity
HP
Damage
Red Storm lightning magic 55-110 8-18
Storm Rider magic  lightning 60-120 8-18
Storm Lord magic lightning 75-135 12-24
Maelstorm magic lightning 90-150 15-28

Gargoyles, onced sanctioned to protect humans, was subdued by Diablo n turned against those whom they were sworn to protect. In the dark, they stand still, but one move n the pack is alerted.

Gargoyle Type
Resistance
Immunity
HP
Damage
Winged Demon none fire, magic 45-60 10-16
Gargoyle none lightning, magic 60-90 10-16
Blood Claw none magic, fire 75-125 14-22
Death Wing none magic, lightning 90-150 16-28

Balrogs resemble the typical human impersonation of a demon. Winged and big. Balrogs spit out streams of fire in a single direction. Close one down fast before he takes a shot at you. Fire resistance very advised when facing these foes.

Balrog Type
Resistance
Immunity
HP
Damage
Slayer magic fire 60-100 12-20
Guardian magic fire 75-112 14-26
Vortex Lord magic fire 87-125 18-36
Balrog magic fire 100-150 22-40

In the deep recesses of the Caves n Hell, you'll encounter a foe that resembles a giant snake, the viper. These demons are swift, and normally swarms you in numbers. Take them out one at a time.

Viper Type
Resistance
Immunity 
HP
Damage
Cave Viper none magic 100-150 8-20
Fire Drake fire  magic 120-170 12-24
Gold Viper lightning magic 140-180 15-26
Azure Drake fire, lightning none 160-200 18-30

In the levels of Hell, Knights will appear. These demons are though, and possess armor equivilent to yours. The later knights possess numerous immunities, so physical damage is probably the only factor that can harm these beings.

Knight Type
Resistance
Immunity
HP
Damage
Black Knight lightning, magic none 150 15-20
Doom Guard fire, magic none 165 18-25
Steel Lord lightning, magic fire 180 20-30
Blood Knight fire lightning, magic 200 25-35

The succumbi kin will prove to be one of the most devastating foe you will face. They spray bolts of magi towards your direction, so you are advised to be constantly moving to dodge the magic. Herd them one-by-one into a wall and take the pleasure of finishing her.

Succubi Type
Resistance
Immunity
HP
Damage
Succubus magic none 120-150 1-20
Snow Witch lightning none 135-175 1-24
Hell Spawn magic lightning 150-200 1-30
Soul Burner magic, lightning fire 140-225 1-35

Counselors are probably the deadliest enemy you will face, before your showdown with the Lord of Terror. They teleport around the area and spray you with Fireballs n Charged Bolts. Quickly move towards one and slash as fast as you can before he can teleport away.

Counselor Type
Resistance
Immunity
HP
Damage
Counselor magic, lightning, fire none 70 8-20
Magistrate magic, lightning fire 85 10-24
Cabalist magic, fire lightning 120 14-30
Advocate fire lightning, magic 145 15-25