These legendary figures and deities, deeply embedded in various cultures and religions, represent hope and the timeless belief in the eventual return of saviors and heroes.

1. **King Arthur**: The legendary British leader who, according to medieval histories and romances, led the defense against Saxon invaders. Prophecies often suggest that Arthur, the "Once and Future King," will return in Britain's hour of need.

2. **Jesus Christ**: In Christian theology, Jesus is believed to return during the Second Coming to judge the living and the dead and establish God’s kingdom.

3. **Osiris**: The ancient Egyptian god of the afterlife, resurrection, and fertility. Mythology tells of Osiris being resurrected by his wife Isis, hinting at a return.

4. **Quetzalcoatl**: The feathered serpent god of Mesoamerican mythology, especially among the Aztecs and Toltecs. Legends say he will return one day to reclaim his throne.

5. **Gilgamesh**: The Sumerian king of Uruk, who is the hero of one of the earliest pieces of literature. Some legends hint at his return to bring wisdom and leadership.

6. **King Gesar**: The legendary hero of Tibet, celebrated in the Epic of King Gesar. His return is prophesied to restore order and justice.

7. **Robin Hood**: The English folk hero who, according to legend, will return in times of need to fight tyranny and help the poor.

8. **Mahdi**: In Islamic eschatology, the Mahdi is the prophesied redeemer who will appear before the Day of Judgment to restore justice.

9. **Maitreya**: In Buddhist tradition, Maitreya is the future Buddha who will come to teach the pure dharma and achieve complete enlightenment.

10. **Zarathustra (Zoroaster)**: The prophet of Zoroastrianism, who is prophesied to return to vanquish evil and restore righteousness.

These legendary figures and deities, deeply embedded in various cultures and religions, represent hope and the timeless belief in the eventual return of saviors and heroes.

**Kalki** is indeed one of the most significant figures in Hindu eschatology. According to Hindu beliefs, Kalki is the prophesied future incarnation of the god Vishnu, who will appear at the end of the current age, known as Kali Yuga. Kalki is expected to come riding a white horse, wielding a sword, to restore righteousness (dharma) and eradicate evil from the world. This avatar is believed to bring about the end of the present age of darkness and corruption, leading to a new era of truth and virtue.