Siegfried with the Schwarzwind group
Schwarzwind (German for "black wind") are a group of fictional characters within the Soul series. Siegfried began to socialize with them prior to the events of Soul Blade, and he soon became the leader of their band of thieves. After disbanding from them after accidentally killing his father, he reunited with them in his Soul Calibur ending (although likely non-canon, since there was no statment that he joined the the group again in Soul Calibur II and Soul Calibur III, because Siegfried was seeking atonement for his sins.). After the events of Soul Calibur IV, Siegfried reformed the Schwarzwind into a clan of mercenaries. Among others, members include Salia Olschmidt and, as of Soulcalibur V, Hilde.
A sketch of the Schwarzwind group that was released on Daishi Odashima's twitter
Siegfried with the Schwarzwind group from his Soul Calibur ending