Finnish mythology is rich and vivid with multiple deities. Most worshiped of all deities is Ukko.
God of the sky, harvest, thunder, rain, snow and clouds.
It is believed that Ukko was one of the first and primary god worshiped by ancient Finns.
In agricultural world god who provided thunder and rain was the most important.
From the word Ukko also comes Finnish word Ukkonen which means thunder
People also preyed Ukko for prosperity, peace and love...you name it.
Ukko was celebrated during midsummer in the festival called Ukon vakat.
This party included dancing, drinking, singing and eating.
It was also great time for doing spells, especially love spells.
Ukon Vakat was celebrated all over Finland.
Most often festival place was in an island, on a hill or by the lake.
From these habits drinking and eating have remained to this day in modern Finnish Midsummer celebration but now days it's mostly Finnish neo-pagans who raise their glass to honor gods.
Especially children 'till this day do love spells during the Midsummer solstice.
Burning Bonfires during midsummer solstice is also common habit from pre-christian eras.
It was believed that Bonfires kept evil spirits away.
Ukko was respected and loved god but also feared because his powerful elements.
Both Finnish people and Sami people who worshiped Ukko were careful not to speak about him unrespectfully. For Ukko might get angry and revenge.
Taken around midsummer
Earth and sky together
Ukko's holy animal is the eagle. If you are familiar with native american myths they have lot's of stories about thunder birds (eagles). Ukko's eagle is based on the same idea and it's popular also in Siberian and Baltic myths.
If person saw eagle flying just before thunder started that was considered as a very good omen.
Idea of thunder god as the ruler god is extremely popular in European cultures.
In Greek mythology Zeus is ruler of the gods, skies and thunder.
In Norse mythology Thor is blacksmith god of thunder.
In Lithuania Thunder god is known as Perkunas and Perkos in Latvia.
Finnish word Perkele was originally one name for Ukko as well. Since the reformation sadly word Perkele is now a curse word and has been associated with the devil because of the early church fathers who didn't approve old pagan gods.
All these gods have similar descriptions.
Muscular men with long beards.
Ukko has two aspects.
Sometimes around Finland's Iron Age around 500 bc. Ukko got two roles. He wasn't anymore just one god, he became two gods. Ilmarinen is Ukko's other aspect.
Ilmarinen is a blacksmith god who created Iron and also the first Fire.
Ukko still remained as god of agriculture and thunder.
My personal guess is that this another aspect of Ukko; Ilmarinen was born around the same time when Finnish tribes started to trade with vikings and got influenced by Nordic/Germanic Folklore. There was also first travelers from Rome which was the leading culture in Europe at the time. Ilmarinen as a god is similar to Nordic blacksmith thunder god Thor.
Iron Age was a big cultural transformation in Finland with new technical inventions. That has also made Ilmarinen Finnish cultural-hero figure. First poems and stories from Finnish anthology Kalevala are from the early iron age. That is why Ilmarinen is also one hero-character in Kalevala as well.
Ilmarinen is also part of world birth myth. He build the cover of the sky and nailed stars to the heaven. As ruler of winds fishermen also prayed Ilmarinen for good fishing luck.
For ancient Finns Ukko was also a honorable name given for a man who had reached high age.
In modern Finnish language Ukko means an old man.
Ukko/Ilmarinen is usually described holding an ax.
Occasionally also a lightning in his hand.
Ukon Vaaja / Ukko's Axe
Akka is goddess of the earth, fertility and storms.
Unfortunately there is way less info about Akka than there is about Ukko.
I guess the reformation done in Finland around Middle-Ages was really unfair for the Finnish female deities. We do now that Akka is Ukko's spouse.
Akka also has another name, Rauni.
Name Rauni is believed to come from Swedish word Rönn, that means Rowan tree in English.
Rowan tree is considered to be very powerful magical tree. Great name for an earth goddess
(Rauni is also Finnish woman's name).
Akka was also a honorable name given for a woman who had reached an old age.
Both gods have big part on one of the first fertility myths.
When thunder is approaching Akka takes a form of a seamaiden.
She rises from the water and Ukko takes a form of lightning and strikes her. Sky and earth literally combine.