ive been puzzling on how to fit kirins into my elaborate lore for the mlp universe but i think ive landed on a headcannon that makes me happy : )

SO kirins were once ponies, descending from unicorns who traveled deep into the mountains during the thousand year war. during the ice age brought about by the pegasi, they were on the brink of starvation, and were losing hope of surviving. they were saved by the great seeding, the deer spirit who took pity on the unicorns, sympathizing with their desire to escape the war. he offered to make their new home a place of bountiful harvest and mild winters in exchange for their service to him. all he asked was that they protect and care for their forest, and give tribute each harvest in his honor. the unicorns agreed and the great seedling used his magic to transform them into the kirins, whose magic is best suited to care for plant life, and whose bodies could withstand the harshness of the peaks of peril. nowadays kirin are on average taller and more slender than their pony cousins, and hybrids between the two are rare and often result in sterile offspring with volatile magic.

When the kirin village accidentally caused a forest fire, destroying much of the land the great seedling had given them, they took drastic measures to ensure such a disaster would never happen again. when they at long last began to speak again, autumn blaze was welcomed back into the village and has lived happily amongst her kind since, though she often vacations in ponyville to see her friends.