They are chaotic to reflect their home the ever changing chaos of Limbo.
According to lore Primus the overlord of the modrons who lives in Mechanus, the plane of
neutral law, crafted a powerful stone and imbued it with the power of law.
This stone was supposed to bring order to chaos wherever it went.
Primus had a plan for this stone and it was to send it into Limbo to tame the chaos of
that realm.
The plan didn’t work out as Primus intended though.
Yes it did bring some order to the minds of certain inhabitants of Limbo, this allowed
modrons and the githzerai to create enclaves in Limbo.
However, the chaos of Limbo was too strong, or just can’t be tamed in general nobody
is sure.
The stone started to absorb so much of the chaotic energy of Limbo it spawned the horrors
that became known as the Slaad.
This stone probably once had another name but it has been forgotten and is now known
as the spawning stone to the Slaad and the rest of Limbo.
The Slaad then destroyed all the modron enclaves in Limbo.
The Slaad being creatures of chaos detested the mordorons who were creatures of Law.
To this day they will attack the modorons on sight.
Slaads are weird, hailing from the plane of chaos they are probably expected to be weird.
They reproduce by implanting a humanoid host with eggs, or infecting them with a transformative
disease called chaos phage.
There are different types of Slaad that are defined by their different colors.
There are Red Slaad, Blue Slaad, Green Slaad, Gray Slaad and Death Slaad.
Each color of slaad reproduces or transforms in a different way.
Red Slaad spawn blue and green.
Blue Slaad spawn red and green.
Green Slaads undergo a lifelong cycle of transformation into the more powerful gray and death slaads.
A Red slaad claw can inject an egg from a gland.
The egg works its way into a host and gestates, eventually forming a slaad tadpole.
The tadpole then eats away at the host nourishing it.
It then transforms into a fully grown blue slaad.
The gestation period I read in the 4th edition Monster Manual was 1d4+3 days.
However in the Planescape Monstrous Compendium it said that the blue slaad gestation period
was 3 months!
This egg or tadpole can be destroyed through a greater restoration or remove curse spell
to save the host.
If the host was a spellcaster of 3rd level spells or higher the slaad will be green instead.
Blue slaads have bone hooks on their back that when touched inflict a transformative
disease, similar to lycanthropy.
The infection is called chaos phange and will transform the victim into a fully grown red
slaad, or green if the victim was a spellcaster of 3rd level spells or higher.
This transformation takes around 3 months according to the Monstrous Compendium again.
The disease is undetectable in the first month except through a detect evil or other magic.
After that the effects become obvious and a cure disease spell or similar magic is necessary
to rid the disease.
Because of this slaad often take prisoners to ensure their offspring come to fruition.
Green slaads are spellcasters, surprise.
They are intelligent and can cast a few spells innately.
It’s able to change its shape to appear humanoid and will often take the disguise
of the host it spawned from or the victim it transformed from.
At some point, after a century or so, a green slaad will magically transform into a Gray
Slaad.
Becoming a more powerful slaad and magic user.
Gray slaad are often found on the material plane doing the bidding of their masters the
death slaad.
They often take humanoid form and have learned to master the greatsword, which they imbue
with magical power.
A gray slaad that eats the entire corpse of a death slaad transforms into a death slaad.
Death slaad are gray slaad that have been infused with energy from the negative energy
plane.
It amplifies the chaos and evil within their hearts.
They are the generals of slaad armies, and push red and blue slaads to attack other planes
which will hopefully propagate their species.
Slaad have huge heads and their claws are extremely sharp.
They speak their own language but also have limited telepathy which allows them to understand
and converse with other intelligent beings.
Slaad observe an informal and pragmatic hierarchy, not because they respect regulation, but rather
because strong rulers destroy disobedient underlings.
Slaad will scavenge battlefields removing wounded victims to be used as hosts for future
slaad.
Slaads have gems in their heads.
Like deep in their brains, the size of a baseball there is a magical stone.
Slaads get this stone if they came from the spawning stone, or if they ever visit it which
new slaads are instinctually driven to do.
The stone is the same color as the slaad and can be used for control.
It’s as if the spawning stone magically implants a fragment of itself inside the slaads
brain.
Another creature can magically or surgically remove the gem from the slaad.
If this happens the slaad must obey whoever possesses its gem.
This is handy for high level wizards who are looking for a loyal servant.
It takes some high level magic to remove the gem though.
The imprisonment spell can transfer the gem to the spellcaster’s open hand instead of
imprisoning the slaad.
Also a wish spell.
Otherwise it’s a DC20 medicine check to surgically remove the gem, good luck with
the Slaad holding still during this process.
That’s it for Slaad!
I’ve always like frogs and toads so I have a fondness for the slaad.