Final answer:
Krishna is the avatar of Vishnu in the Bhagavad-gita and plays a significant role in the teachings of the text.
Step-by-step explanation:
The avatar of Vishnu, the lord, in the Bhagavad-gita is Krishna. In the Bhagavad Gita, Krishna is depicted as a chariot-driver who gives a lecture to Arjuna, a disciple. He explains the difference between just and unjust wars, the importance of loyalty to one's family, and religious themes concerning the relationship between the soul of each individual and the soul of the world.