Krishna (कृष्ण) literally "dark, black, dark-blue" is a Hindu god, whose conversation with the warrior Arjuna, has been documented in the Bhagavad Gita. In some monotheistic traditions, Krishna is considered an avatar of Vishnu, one of the three gods of the Holy Trinity, and the preserver of Creation.
Agni (Sanskrit: अग्नि) is a Hindu deity, the god of fire and the acceptor of sacrifices. Agni is considered to be the messenger to the gods, and hence the sacrifices made to Agni during a “havan” or “yagya” are directly sent to the gods. Agni is immortal because a fire is lights up bright and strong, each time of being lit.