Pirun is a young girl from Luberia who greatly admires Nanashi. She knows Nanashi from when he saved her when she was under the attack of several Chess Pieces, but it was too late for her parents. Pirun and Nanashi would grow close together, with Pirun affectionately calling Nanashi "brother".
Nanashi would later give Pirun a holy ÄRM. However, soon after, Pirun and many other Luberians would be killed by Peta during his attack on Luberia's base. During the Final Battle, when Nanashi fought with Peta to avenge Luberia, Pirun appears, praying for Nanashi to be protected. Pirun's holy ÄRM, Aegis, would revive Nanashi, granting him victory.