Lightning Magic

"Ukko, thou O God above me, Thou the father of creation, Thou that speakest through the thunder, Thou whose weapon is the lightning, Thou whose voice is borne by ether, Grant me now thy mighty fire-sword, Give me here thy burning arrows, Lightning arrows for my quiver, Thus protect me from all danger..."
(Kalevala, trans. John Martin Crawford)
Niflheim sits atop the world. Muspelheim sits far south, well down below the known world. Alfheim is an ocean away, where Leif Ericson earned his fame and but few northern men have trod. Though Midgard itself is not without its dangers - an errant giant sometimes finds a human settlement - none were less fortunate than the Finns, who awoke after Ragnarok among the grey, lifeless trees of troll-haunted Ironwood.
When shelter and food was the most pressing concerns of those on the continent, the men and women of Finland were fleeing for their lives from giantesses and giant wolves. The Finns, masterful sorcerers by reputation, were powerless to defend themselves from their hunters, who were shielded from seid by the ancient wards of their troll-mothers and the singular, evil intent in their own hearts. So it was that Earth’s mightiest magicians were laid low, unable to preserve themselves, let alone their homes.
And darker times were yet to come. Bosi hoggvandil, a half-giant, found a following on the edge of the Ironwood. An unholy bond formed between the troll-wives and the deformed half-giant. Bosi fathered all manner of demons and devils to plague the woods. It was one of these troll women, Herja, whom portended Bosi’s death would come at the hands of a Finnish sorcerer. It was this foretelling that turned the Finns from incidental prey to hunter’s quarry.
Of his sons and their mothers, and from his own bodyguard, the hefnandi, Bosi demanded the head of every sorcerer, shaman, mystic, and mage. These were happily given. The magician’s mouths were sewn shut, and many dozen now hang from the rafters of Bosi’s throne room. In finding their prey, the hunters destroyed many makeshift villages and stole many innocent lives. As word spread of the attacks, the few remaining magicians were cast out to fend for themselves.
The first Ukkonen were five sorcerers and shamans who, bloodied from days of pursuit, were pressed to make a stand against a dozen troll-wives and their sons. They had been traveling south in hopes of finding a ship to take them to the continent when they were set upon. In desperation they invoked Ukko, the highest, god of sky and thunder, with prayer, clutching ukonvasara.
Ukko answered. A colossal thunderbolt crashed down between predator and prey. The trolls and wolves were killed instantly, cooked within their skins, and the five magicians were knocked unconscious. When they awoke, dressed only in the burnt flesh of their enemies, they found themselves branded with the tortuous sign of Ukko creeping up their spines like a snake. In stories, Ukko demonstrates his power only through natural phenomena – sudden storms of icy rain and hail, or a mighty lightning-arrow streaking through the sky. Here, though, the sorcerers were given a measure of his power to wield for themselves.
The five returned to their village with little difficulty, for lightning is a potent weapon against trolls and their ilk, and found it overrun with all manner of Ironwood-folk. They threw lightning as spears and arrows from their ukonvasara, and they flung out the wretched invaders with mighty gusts of wind. They gripped tight their ukonvasara and, shouting Ukko’s praises, were nigh on invincible. Their enemies defeated, they liberated the townspeople, who hailed them as heroes. They called them Ukkonen, “thunder,” because their presence presages lightning.
The five Ukkonen resolved to win back their homeland. Aallotar went east; Juoksa, west; Heimo, north, and Jarki, south. Eetvartti remained behind to guard their homes. Their mission is to awaken the power of Ukko’s lightning in those strong of mind and spirit, and to repay the Bosi for his bloody crimes.