The following material is Open Game Content from the Menace Manual SRD
Fiends appear in countless forms, although their physical characteristics often reflect some sin or other vile aspect.
Fiends share the following traits:
Darkvision (Ex): Fiends have darkvision out to a range of 60 feet. Darkvision is black and white only, but it is otherwise like normal sight, and a fiend can function with no light at all.
Allegiances: All fiends have a primary allegiance to evil. Fiends may also have an allegiance to either chaos or law.
Weapon and Armor Proficiency: Fiends receive either Archaic Weapons Proficiency or Simple Weapons Proficiency as a bonus feat. They are proficient with their natural weapons and any weapon mentioned in their entries. Fiends noted for wearing armor gain the bonus feat Armor Proficiency with whatever type of armor they are accustomed to wearing (light, medium, heavy), as well as all lighter types.
Languages: Fiends can speak Abyssal (the language of demons) and a number of additional languages equal to their Intelligence bonus. Fiends with an Intelligence of 8 or higher can also read and write these languages.
Special: Fiends cannot be raised from the dead.
Kwevencha (Spider Fiend)
Damage Reduction 5/Silver (Ex): A kwevencha ignores the first 5 points of damage dealt by any unsilvered weapon.
Immunities (Ex): A kwevencha is immune to poison.
Improved Grab (Ex): To use this ability, the kwevencha must hit a Small or Medium-size creature with its bite attack. If it gets a hold, it deals automatic damage with its bite on subsequent rounds.
Monstrous Spider Minions: A kwevencha has 2d6 Tiny monstrous spiders clinging to its body. It can telepathically command these spiders to attack, but the kwevencha must remain within 100 feet of the monstrous spiders to telepathically control them.
Poison (Ex): Bite; contact 1d6 Str/1d6 Str; Fortitude save (DC 10 + 1/2 the kwevencha’s Hit Dice + its Constitution modifier) resists.
Spit Poison (Ex): A kwevencha can shoot a 20-foot-long line of poisonous spittle at a single target. The save DC and effects of the poison are described above.
Stability (Ex): A kwevencha gains a +4 stability bonus on checks to resist trip and bull rush attacks.
Telepathy (Su): A kwevencha can communicate telepathically with any creature within 100 feet that has a language.
Web Cocoon (Ex): A kwevencha uses a spinneret in its abdomen to weave web cocoons around creatures incapacitated by its poison. A creature trapped inside the cocoon is immobile, although breathing is possible through the porous webbing. A kwevencha’s web cocoon has 20 hit points and a break DC of 26. Dealing damage to the web cocoon deals a like amount of damage to the creature trapped inside.
Skill Bonuses: A kwevencha gains a +4 species bonus on Balance, Climb, Jump, and Spot checks.
Kwevencha (spider fiend): CR 7; Large outsider; HD 8d8+24; hp 60; Mas 20; Init +0; Spd 30 ft., climb 30 ft.; Defense 23 (–1 size, +14 natural), touch 10, flat-footed 23; BAB +8; Grap +18; Atk +13 melee (1d8+6 plus poison, bite) or +7 ranged touch (poison spittle); Full Atk +13 melee (1d8+6 plus poison, bite) and +8 melee (1d6+3, 2 claws) or +7 ranged touch (poison spittle); FS 10 ft. by 10 ft.; Reach 5 ft.; SQ Damage reduction 5/silver, darkvision 60 ft., immunities, improved grab, monstrous spider minions, poison (DC 17), spit poison, telepathy, web cocoon; AL chaos, evil; SV Fort +9, Ref +6, Will +7; AP 0; Rep +0; Str 22, Dex 11, Con 17, Int 8, Wis 13, Cha 12.
Skills: Balance +11, Climb +17, Hide +3, Intimidate +8, Jump +13, Listen +8, Move Silently +7, Read/Write Abyssal, Speak Abyssal, Spot +12.
Feats: Improved Damage Threshold, Iron Will.
Advancement: 9–14 HD (Large); 15–21 HD (Huge); or by character class.