Newly Sentient

The flawed use of Mass Resurrection has gifted self-awareness to a variety of once unintelligent creatures. Once affected, their intelligence develops wildly, and they can learn a new language in just a few months. The change is often paralleled by physical boons, stronger bodies to accommodate their minds.
Their category goes by lots of different names: awakened, insighted, propesentient, qualiard, wary, were-y, wacu. Creatures affected by the "Awaken" spell are similarly described.

Development

Wacu have a variety of reactions to their newfound awareness, and it's an ordeal to manage on their own. The process of awakening is difficult to track, but it tends to come in a few noticeable stages.

Lucid nightmare

(Translated by the Speak with Animals spell)
"Of course I'm mad at you. You killed me.
No, but I'm still alive. I'm sorry, forget what I said.
But I'm so confused now! I think I need help?"

New waries try to continue their lives as normal, but they can't do so for long. They sleep much more deeply than they used to, as they try to process their vastly expanded thoughts. They might have trouble distinguishing reality from their expanded imaginations, even years after they awaken.
Wacu can visualize things that aren't real, and they can reason beyond their instincts. Their old lives of hunting or gathering make them restless, and eventually they have to set foot into this new dimension.

Scraps of magic

(Translated by the Speak with Animals spell)
"Is someone there? Help us! You're here to help, right? Do something! Cure--please heal--uh--c-cure--what's--what do I----Cure Wounds!
...
Thanks. Sorry I yelled at you."

In a moment of inspiration or duress, the lively magic affecting a wacu might allow them to make contact with Botryte and ask her for help. She will often respond to the plea without question--she has trouble concentrating in the hours that follow a resurrection. In their first few days of awakened life, some wacu can use a bit of divine magic when they really need it.
Even after the side effects of the spell are cleaned up, wacu may express a talent or interest in this kind of magic. Botryte herself still talks to a few of them.

Supernatural growth

"What do you mean? I don't understand.
Could you try the 'Speak with Animals' spell again?
Wow...I don't think that spell will work for much longer."

The magic that awakened a wacu tends to follow them out, affecting their minds in a way that lets them catch up with other sentient creatures.
They might learn new words and grammar which they heard only in passing. They collect new ways of reasoning without being taught, just by the way they naturally listen. When someone else instructs them, they digest information at incredible speed. Eventually their development slows to a more reasonable pace, but a person who observes wacu, as they grow markedly more thoughtful with each passing day, may fearfully wonder if there's any limit to their ability.
Wacu are especially good at self-instruction if they're adults at the time of awakening. The maturity of an experienced creature, mixed with the learning speed of a newborn, can produce a being of remarkable talent.

Lazy genius

"Good work, everyone. I'm taking a break. Wake me up when the wolves find us."

Most sentient peoples of Agrophon evolved from endurance-hunters, and have the ability to work and think for many hours at a time. By comparison, wacu take frequent rests and seem to spend most of their time sleeping, especially if they were created from smaller animals. But they aren't as lazy as they seem, and a wacu who sleeps all day might seem to wake up twice as intelligent.
People, wacu or not, process information even when their conscience is taking a break. Sleep is important for creatures who are experiencing a new world in a very short time.
When fully developed (whatever that means--definitions vary), wacu can be as productive as any other creature despite the relatively short time they spend awake. They operate in short bursts of energy, and they can fluently drift in and out of sleep while working on a difficult task, considering the problem subconsciously and waking up with new ideas.

Elevated Niche

"Let's see, where are the twin stars? There. So we're about...12 miles from home in...that direction. Oh, or 10 if that storm hits us. The earth shrinks when it rains, you know."

Even when a wacu's development is largely complete, they aren't intelligent in quite the same way as other creatures. Their origin and their instincts affect their skills in odd ways. The wacu spawned by each Mass Resurrection seem to be more bizarre than the last.

Wacu from each Mass Resurrection

Each resurrection produces a vastly different strain of newly sentient characters, depending on the nature of the spell and the environment where it's cast.
Developments - Act I

Suthermont

The spell was performed under good conditions, but as a trial run, the cleric had many unanswered questions. Today the spell would be considered a mild failure, but to the distraught researchers, it was a nightmare. A lot of magical energy was spent on awakening a pair of anthills, who battled for a few weeks until both were nearly extinct. A swarm of wacu were summoned, and the resurrected citizens hastily tried to stomp them out, underestimating their numbers and strength.
The Suthermont Wacu are mostly bugs and large animals, plus some manmade structures and a disproportionate number of magical beasts. They tend to be extremely intelligent and capable in a fight, with a generally bitter view of the rest of Agrophon. The few that escaped Suthermont have become well-known monsters and public enemies, but they've gotten very good at avoiding detection. Symbols of the infamous Suthermont failure, they don't expect to be welcome anywhere.

Aevaly

The Aevaly Wacu fared much better than those in Suthermont. Mostly giant rats, giant bats, and a few other animals, they incredibly shifted from a looming threat to a natural part of civilization, and were among the founders of New Aevaly. They began to put the frightening intelligence of wacu in a positive light, and found places to live, almost in peace, throughout Agrophon.

Developments - Act II

The Stole Fixture

When a cleric trained to perform Mass Resurrections went rogue, the spell was cast with no intention of bringing everyone back. Instead it summoned a massive ecosystem of wacu, bred specifically to be monsters. They mostly consist of living swamp plants twisted into animal forms, which constantly evolve by fighting each other, destroying and rebuilding themselves in search of stronger bodies. In addition to the plants, there are lots of wary creatures among them, mostly bugs, and a few creatures in between--plant matter infused with animal flesh and bone. From the way these wild plants grow and change, it's difficult to tell which parts of them are dead, alive, and sentient.
Thanks to deliberate misuse of the Mass Resurrection, these creatures became sentient but not quite lucid. Enthralled by the cleric's lingering command, they moved around in a dreamy state, their developing minds trapped in their animal instincts, spared from the consequences of their actions. To make things worse, this magical influence somehow gave them a gleeful obsession with violence. They could hear the arguments and pleas from those who tried to reason with them, but they didn't seem to internalize any of the words. They would talk and cavort in a friendly manner while continuing their vicious conquest of everything in their path.
But even with magical compulsion, there are exceptions to their exaggerated mob mentality. With enough time, the Stole creatures can eventually calm down and question the parameters of their lives. Some are excited to change for the better, but others sink deeper into sadism, afraid to accept responsibility for what they've already done.

Developments - Act III

The Kudoan Seaside

For all the flaws of the Mass Resurrection in Suthermont, it could have been much worse: the planners were extremely careful that the effects of the spell did not reach the sea. That fear was realized by the misused resurrection off the coast of Kudo.