Encounter 4 - lvl 5 to 10

1x Barbed Devil Medium fiend (devil) , lawful evil
Armor Class 15 (Natural Armor) Hit Points (13d8 + 52) Speed 30 ft.
STR 16 (+3) DEX 17 (+3) CON 18 (+4) INT 12 (+1) WIS 14 (+2) CHA 14 (+2)
Saving Throws STR +6, CON +7, WIS +5, CHA +5 Skills Deception +5, Insight +5, Perception +8 Damage Resistances Cold; Fire; Bludgeoning, Piercing, and Slashing from Nonmagical Attacks that aren't Silvered Damage Immunities Poison Condition Immunities Poisoned Senses Darkvision 120 ft., Passive Perception 18 Languages Infernal, Telepathy 120 ft. Challenge 5 (1,800 XP) Proficiency Bonus +3
Barbed Hide. At the start of each of its turns, the barbed devil deals (1d10) piercing damage to any creature grappling it.
Devil's Sight. Magical darkness doesn't impede the devil's darkvision.
Magic Resistance. The devil has advantage on saving throws against spells and other magical effects.
Actions Multiattack. The devil makes three melee attacks: one with its tail and two with its claws. Alternatively, it can use Hurl Flame twice.
Claw. Melee Weapon Attack: +6 to hit, reach 5 ft., one target. Hit: (1d6 + 3) piercing damage.
Tail. Melee Weapon Attack: +6 to hit, reach 5 ft., one target. Hit: (2d6 + 3) piercing damage.
Hurl Flame. Ranged Spell Attack: +5 to hit, range 150 ft., one target. Hit: (3d6) fire damage. If the target is a flammable object that isn't being worn or carried, it also catches fire.
1x Bearded Devil Medium fiend (devil) , lawful evil
Armor Class 13 (Natural Armor) Hit Points (8d8 + 16) Speed 30 ft.
STR 16 (+3) DEX 15 (+2) CON 15 (+2) INT 9 (-1) WIS 11 (+0) CHA 11 (+0)
Saving Throws STR +5, CON +4, WIS +2 Damage Resistances Cold; Fire; Bludgeoning, Piercing, and Slashing from Nonmagical Attacks that aren't Silvered Damage Immunities Poison Condition Immunities Poisoned Senses Darkvision 120 ft., Passive Perception 10 Languages Infernal, Telepathy 120 ft. Challenge 3 (700 XP) Proficiency Bonus +2
Devil's Sight. Magical darkness doesn't impede the devil's darkvision.
Magic Resistance. The devil has advantage on saving throws against spells and other magical effects.
Steadfast. The devil can't be frightened while it can see an allied creature within 30 feet of it.
Actions Multiattack. The devil makes two attacks: one with its beard and one with its glaive.
Beard. Melee Weapon Attack: +5 to hit, reach 5 ft., one creature. Hit: (1d8 + 2) piercing damage, and the target must succeed on a DC 12 Constitution saving throw or be poisoned for 1 minute. While poisoned in this way, the target can't regain hit points. The target can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success.
Glaive. Melee Weapon Attack: +5 to hit, reach 10 ft., one target. Hit: (1d10 + 3) slashing damage. If the target is a creature other than an undead or a construct, it must succeed on a DC 12 Constitution saving throw or lose (1d10) hit points at the start of each of its turns due to an infernal wound. Each time the devil hits the wounded target with this attack, the damage dealt by the wound increases by (1d10). Any creature can take an action to stanch the wound with a successful DC 12 Wisdom (Medicine) check. The wound also closes if the target receives magical healing.
2x Imp Tiny fiend (devil) , lawful evil
Armor Class 13 Hit Points (3d4 + 3) Speed 20 ft., fly 40 ft.
STR 6 (-2) DEX 17 (+3) CON 13 (+1) INT 11 (+0) WIS 12 (+1) CHA 14 (+2)
Skills Deception +4, Insight +3, Persuasion +4, Stealth +5 Damage Resistances Cold; Fire; Bludgeoning, Piercing, and Slashing from Nonmagical Attacks that aren't Silvered Damage Immunities Poison Condition Immunities Poisoned Senses Darkvision 120 ft., Passive Perception 11 Languages Common, Infernal Challenge 1 (200 XP) Proficiency Bonus +2
Shapechanger. The imp can use its action to polymorph into a beast form that resembles a rat (speed 20 ft.), a raven (20 ft., fly 60 ft.), or a spider (20 ft., climb 20 ft.), or back into its true form. Its statistics are the same in each form, except for the speed changes noted. Any equipment it is wearing or carrying isn't transformed. It reverts to its true form if it dies.
Devil's Sight. Magical darkness doesn't impede the imp's darkvision.
Magic Resistance. The imp has advantage on saving throws against spells and other magical effects.
Actions Sting (Bite in Beast Form). Melee Weapon Attack: +5 to hit, reach 5 ft., one target. Hit: (1d4 + 3) piercing damage, and the target must make a DC 11 Constitution saving throw, taking (3d6) poison damage on a failed save, or half as much damage on a successful one.
Invisibility. The imp magically turns invisible until it attacks or until its concentration ends (as if concentrating on a spell). Any equipment the imp wears or carries is invisible with it.
2x Lemure Medium fiend (devil) , lawful evil
Armor Class 7 Hit Points (3d8) Speed 15 ft.
STR 10 (+0) DEX 5 (-3) CON 11 (+0) INT 1 (-5) WIS 11 (+0) CHA 3 (-4)
Damage Resistances Cold; Fire Damage Immunities Poison Condition Immunities Charmed, Frightened, Poisoned Senses Darkvision 120 ft., Passive Perception 10 Languages Understands Infernal but can't speak it Challenge 0 (10 XP) Proficiency Bonus +2
Devil's Sight. Magical darkness doesn't impede the lemure's darkvision.
Hellish Rejuvenation. A lemure that dies in the Nine Hells comes back to life with all its hit points in 1d10 days unless it is killed by a good-aligned creature with a bless spell cast on that creature or its remains are sprinkled with holy water.
Actions Fist. Melee Weapon Attack: +3 to hit, reach 5 ft., one target. Hit: (1d4) bludgeoning damage.