What is the role of Octavian in establishing an empire in Rome?

Octavian called himself princeps. So, according to tradition, the first in the list of the Senate was called. The Senate gave him the title of Augustus (in Latin – sacred, exalted). Octavian also assumed the title of Caesar.
Octavian Augustus was the commander-in-chief of all the military forces of the state. He created a special palace guard – praetorian cohorts, which were supposed to protect the person of Augustus. As commander-in-chief, Augustus received the life title of emperor, which was given only for a short time. So the autocracy of Augustus was established.