The armies of the Rus went through several changes over they centuries that they fought in what was Russia.
In the eight-century, the armies contained three types of troops. Druzhina (the troops of the household) the Varjazi (paid mercenaries) and Voi (levies raised locally). Most of the troops forming the Druzhina and Voi would be infantry. Cavalry would normally be hired from nomads on the Steppe. Cavalry would not be a major component of Rus armies till the 10th century when they would begin to have cavalry in the Druzhina.
Much of the combat of this earlier time period was very ritualistic and contained Scandinavian features such as vendettas, challenges and blood prices based on rank.

The best known troops in Rus were the Varjazi/Varangians. These were Scandinavian mercenaries who served only the wealthiest rulers. Many of these Varjazi bands arrived in Russia with their own leaders, who had their own fleets and personal armies. One of these Varjazi leaders was Harald Hardrada, who later became King of Norway. Harald spent many years in Russia and the Byzantine Empire.

Each Rus Prince had his own Druzhina or standing army. The members of the Druzhina were known as Drugs (comrades) and were bound together by oaths and communal loyalty (Zadruzni).
From the eleventh century on, the Druzhina was split into the Malaia (upper) Druzhina consisting of the Otroki (bodyguard), and the Grid (lesser) Druzhina which consistes of ordinary troops, retainers, and servants.

With the development of cavalry, it would be the Druzhinas that would provided the mobile mounted forces for the Rus armies. These were professional soldiers that the Rus leaders could keep in the field longer than the militias and levies who were needed at home to keep produce food and maintain the flow of goods upon which the economy of the towns depended.

The Voi (tribal levies) were mostly foot troops who had little or no armour and fought with spears or axes. They also provided skirmishers and light archers. This would include the lowest quality troops called the Smerd (peasants) who were barely armed and of very poor quality militarily.