Sources
CR
Type
Size
Alignment
Movement

Blue Slaad

Large Aberration, Chaotic Neutral

Armor Class 15 (natural armor)
Hit Points 123 (13d10 + 52)
Speed 30 ft.
STR
20
+5
DEX
15
+2
CON
18
+4
INT
7
-2
WIS
7
-2
CHA
9
-1
Skills Perception +1
Damage Resistances acid, cold, fire, lightning, thunder
Senses darkvision 60 ft., passive Perception 11
Languages Slaad, telepathy 60 ft.
Challenge 7 (2,900 XP)

Traits

Magic Resistance. The slaad has advantage on saving throws against spells and other magical effects.

Regeneration. The slaad regains 10 hit points at the start of its turn if it has at least 1 hit point.

Actions

Multiattack. The slaad makes three attacks: one with its bite and two with its claws.

Bite. Melee Weapon Attack: +8 to hit, reach 5 ft., one target. Hit:12 (2d6 + 5) piercing damage.

Claw. Melee Weapon Attack: +8 to hit, reach 5 ft., one target. Hit:12 (2d6 + 5) slashing damage. If the target is a humanoid, it must succeed on a DC 15 Constitution saving throw or be infected with a disease called chaos phage. While infected, the target can't regain hit points, and its hit point maximum is reduced by 10 (3d6) every 24 hours. If the disease reduces the target's hit point maximum to 0, the target instantly transforms into a red slaad or, if it has the ability to cast spells of 3rd level or higher, a green slaad. Only a wish spell can reverse the transformation.

Lore

In the Ever-Changing Chaos of Limbo, bits of forest and meadow, ruined castles, and isolated islands drift through a tumult of fire, water, earth, and wind. The foremost inhabitants of this inhospitable plane are the toad-like slaadi. Slaadi are undisciplined and have no formal hierarchy, although weaker slaadi obey stronger ones under threat of annihilation.