Your black slaads:
Kodo, Male Black Slaad: CR 15; Medium Outsider (Chaotic, Extraplanar); HD 18d8+90+18; hp 189; Int +6, Speed 30 feet; AC 35 (+6 Dex, +19 natural), touch 16, flat-footed 29; Base Attack/Grapple +18/+26; Full Attack 2 claws +26 melee (3d8+8 plus stun) and bite +24 (2d12+4), or +30/+25/+20 melee (2d6+2d6 negative energy damage+8, all is vile damage); SA Pounce, stun, spell-like abilities, summon slaad; SQ Change shape, damage reduction 15/lawful, darkvision 60 ft., fast healing 10, immunity to sonics, resistance to acid 5, cold 5, electricity 5, and fire 5, telepathy 100 ft.; AL CE; SV Fort+21, Ref+22, Will+20; Str 26, Dex 23, Con 21, Int 18, Wis 18, Cha 24.
Skills and Feats Climb +28, Concentration +18, Escape Artist +27, Hide +27, Intimidate +25, Jump +28, Knowledge (any two) +25, Listen +25, Move Silently +27, Search +25 Spot +25, Survival +15 (+17 when tracking), Use Rope +6 (+8 with bindings); Cleave, Combat Brute [Tactical], Great Cleave, Improved Sunder, Improved Toughness, Multiattack, Power attack, Track
Possessions: Vest of resistance +5, +4 Negative Energy Burst Guisarme, Cloak of Charisma +6, Amulet of natural armor +5, Ring of improved blinking (from Unapprochable East).
Kodo is more of the Spell like ability black slaad. The cloak improes the DC of the saves of all his spell like abilities by +3, so if you want to make sure that finger of death works, Kodo is your man.
Podo, Male Black Slaad: CR 15; Medium Outsider (Chaotic, Extraplanar); HD 18d8+144+18; hp 243; Int +6, Speed 30 feet; AC 35 (+6 Dex, +14 natural, +5 deflection), touch 21, flat-footed 29; Base Attack/Grapple +18/+29; Full Attack 2 claws +29 melee (3d8+11 plus stun) and bite +27 (2d12+5), or +33/+28/+23 melee (2d6+2d6 negative energy damage+11, all is vile damage); SA Pounce, stun, spell-like abilities, summon slaad; SQ Change shape, damage reduction 15/lawful, darkvision 60 ft., fast healing 10, immunity to sonics, resistance to acid 5, cold 5, electricity 5, and fire 5, telepathy 100 ft.; AL CE; SV Fort+24, Ref+22, Will+20; Str 32, Dex 23, Con 27, Int 18, Wis 18, Cha 18.
Skills and Feats Climb +31, Concentration +21, Escape Artist +27, Hide +27, Intimidate +25, Jump +31, Knowledge (any two) +25, Listen +25, Move Silently +27, Search +25 Spot +25, Survival +15 (+17 when tracking), Use Rope +6 (+8 with bindings); Cleave, Combat Brute [Tactical], Great Cleave, Improved Sunder, Improved Toughness, Multiattack, Power attack, Track
Possessions: Cloak of resistance +5, +4 Negative Energy Burst Guisarme, Belt of Giant Strength +6, Ring of Protection +5, Amulet of Health +6.
Podo is the Melee Slaad. He gets in and gets rough.
Dodo, Male Black Slaad: CR 15; Medium Outsider (Chaotic, Extraplanar); HD 18d8+90+18; hp 189; Int +9, Speed 30 feet; AC 38 (+9 Dex, +14 natural, +5 deflection), touch 24, flat-footed 29; Base Attack/Grapple +18/+29; Full Attack 2 claws +29 melee (3d8+11 plus stun) and bite +24 (2d12+5), +33/+28/+23 melee (2d6+2d6 negative energy damage+11, all is vile damage); SA Pounce, stun, spell-like abilities, summon slaad; SQ Change shape, damage reduction 15/lawful, darkvision 60 ft., fast healing 10, immunity to sonics, resistance to acid 5, cold 5, electricity 5, and fire 5, telepathy 100 ft.; AL CE; SV Fort+21, Ref+22, Will+20; Str 26, Dex 23, Con 21, Int 18, Wis 18, Cha 18.
Skills and Feats Climb +28, Concentration +18, Escape Artist +27, Hide +27, Intimidate +25, Jump +28, Knowledge (any two) +25, Listen +25, Move Silently +27, Search +25 Spot +25, Survival +15 (+17 when tracking), Use Rope +6 (+8 with bindings); Cleave, Combat Brute [Tactical], Great Cleave, Improved Sunder, Improved Toughness, Multiattack, Power attack, Track
Possessions: Cloak of resistance +5, +4 Negative Energy Burst Guisarme, Gloves of Dexterity +6, Ring of Protection +6, Belt of Giant Strength +6.
Dodo is the tanker sladd his slightly better AC, and slightly lower hit points make him foil for Podo. They should flank if possible, and try to threatn the cansters.
If you think that the gear is too much for the party then curse all of it (so only evil alignments can handle it.) Something like 3 negative levels for a good character and 1 negative level for a neutral character who hold the item in question. Also if they grapple the Sladdi feel free to impose this penality (several times if applicaple.)
Negative Energy: Upon command, a negative energy weapon is sheathed in shadowy black energy. The energy does not harm the wielder. The effect remains until another command is given. A negative energy weapon deals an extra 2d6 points of negative energy damage on a successful hit. All damage caused by the weapon is considered vile damage. It bestows three negative levels on any good creature attempting to wield it. The negative levels remains as long as the weapon is in hand and disappear when the weapon is no longer wielded. This negative levels never results in actual level loss, but it cannot be overcome in any way (including restoration spells) while the weapon is wielded. Bows, crossbows, and slings so crafted bestow the negative energy upon their ammunition. Moderate necromancy; CL 11th; Craft Magic Arms and Armor, harm; Price +2 bonus.
Negative Energy Burst: A negative energy burst functions as a negative energy weapon that also explodes with negative energy upon striking a successful critical hit. The energy does not harm the wielder. In addition to the extra negative energy damage from the negative energy ability, a negative energy burst weapon deals an extra 1d10 points of negative energy damage on a successful critical hit. If the weapon’s critical multiplier is x3, add an extra 2d10 points of negative energy damage instead, and if the multiplier is x4, add an extra 3d10 points. All damage caused by the weapon is considered vile damage. It bestows three negative levels on any good creature attempting to wield it. The negative levels remains as long as the weapon is in hand and disappear when the weapon is no longer wielded. This negative levels never results in actual level loss, but it cannot be overcome in any way (including restoration spells) while the weapon is wielded. Bows, crossbows, and slings so crafted bestow the negative energy upon their ammunition. Even if the negative energy ability is not active, the weapon still deals its extra negative energy damage on a successful critical hit. Moderate Necromancy; CL 15th; Craft Magic Arms and Armor, harm; Price +3 bonus.