He wears a black butler's outfit and is bald. He appears to have four symmetrical scars on his face.
He is very loyal to Rasiel and seemingly has a tendency to make long monologues.
Olgert appears during the Varia's Invasion of the Millefiore's branch in Italy. After Belphegor and Fran split off from the group to scour the area, he and Rasiel confront them. The fight was cut short as Rasiel, having believed that he had killed Bel and Fran with his Storm Bats, led Olgert to the castle that was taken by the Varia. Olgert fought Xanxus in defense of Rasiel, but Olgert, along with his Heavy Rain Elephants and Rain Pelican, was petrified by Xanxus' Box Weapon and his "statue" destroyed.
- Heavy Rain Elephant - Olgert's Rain-attribute Box Weapon. It was stated as a common Box Weapon among Millefiore subordinates, easily controlled and reproduced, with enough power itself to level an entire castle.
- Rain Pelican - Olgert's Rain-attribute Box Weapon. It is able to clad itself in Rain Flames to form a shield.