Who was Dr. Who's first enemy?

Answer 1

The first Doctor had three companions in the first season but as the show went on he had more than one, the first was his granddaughter Susan and the other two were her school teachers there names were Ian and Babara.

Answer 2

In the very first Dr. Who show, An Unearthly Child, the Doctor and his companions go back to prehistoric times. One of the cavemen (Kal) takes a dislike to them, and he might be said to be the Doctor's first enemy.

However it was the second show, The Daleks, which introduced the Doctor's greatest and most enduring enemy, and the first of the recurring enemies.