Zombies

It is believed that four years before the modern era zombies rose up in the Sea of Heavy Sighs during a freak ashfall. There are those who insist they saw it happen and that the unicorn council conclave wiped them out. What is more, these individuals claim that the unicorns slaughtered all witnesses, thus, they had to go into hiding.
Those who think it's BS like to point out immediately that if the unicorns slaughtered all witnesses, how could the witness be telling people about it? They also point out that the unicorns don't like to kill, and the ashfall probably just caused them to hallucinate from air deprivation. The unicorns deny any of it as credible and insist that a volcano must have erupted upwind, causing illness and poisoning in addition to the lack of air from the thick ash. Those who encounter a self-proclaimed witness should turn them over to the unicorns immediately for healing and everyone's well being since the poisons could affect others and possibly even spread. It's for the good of everyone.
The witnesses who survived this so-called incident keep disappearing, some going into hiding, others too ashamed to face their humiliation of being wrong and moving very far away. The unicorns insist that no one goes to the kingdoms that died from the ashfall seeing as the poison could still be strong, and they are not yet certain if the volcano has gone dormant yet. For the safety of self and all, it's best to avoid the area while they keep a watch since their natural purity protects them from such things.
The unicorns have grown a natural vegetation wall around the whole affected area that cannot be seen through, and flyovers are forbidden. Anyone caught inside the barrier is assuredly purified and sent very far away from the temptation for the good of all. Feelings are important to the unicorns, so they would like the public to come immediately to them for counseling if any start to have doubts or confusion. Often, telling others about where these doubts began can help the healing process, and help get to the root of the misunderstandings to clean them out...up. Clean them up. Purify the wicked, and cure the ailments!

Spread

Generally spoken of and questioned only in private amongst the suspicious. Openly complied with by those who still view the unicorns as clean and pure beings who can do no wrong as advertised with the power of the unicorns.

Cultural Reception

Trepidation, mostly.

In Literature

Writing lies is a crime, punishable by the Great Ones. Those of pure light would never possess such harmful blasphemies.

In Art

Unviewed private collections only. One painting series was made by a proclaimed new prophet depicting a Black Unicorn Stallion devastating a Zombie army with gleaming sharp blood-soaked fangs.

Date of First Recording

Four years BME three days in

Date of Setting

Four years BME three days in