The king of Kashi and Karusha. As per Mahabharata Anushasanaparva Chapter 115 verse 64, he was an honest man who gave up his wealth , kingdom and meat eating habits. He was a kinsman of Yama, as per Mahbharata Sabhaparva Chapter 8 verse 18. He gained moksha through dhyanayoga as per Mahabharata Ashwamedhaparva Chapter 33 verses 26-29. He fought the five senses and even decided to cut off his male organ and his five sense organs with arrows. But his mind rebelled. In the end he used yoga to overcome it, as per Mahabharata Ashwamedhaparva Chapter 30.
Once Alarka told a brahmin boy to ask him for any boon. The boy asked for Alarka’s eyes. Alarka dug out his eyes to keep his promise, as per Ramayana Ayodhyakanda Sarga 12 verse 43.