Lord Parashuram

 The Killing of Jamadagni and Parashurama's mother's instruction
A Haihay King Kartavirya Arjuna (Sahasrarjuna - purported to possess a thousand arms) and his army visited Jamadagni, a Brahmin sage, who fed his guest and the whole army with his divine cow Surabhi. The king demanded the magical cow. Jamadagni refused because he needed the cow for his religious ceremonies. King Kartavirya Arjuna (Sahasrarjuna) took the cow forcibly and devastated the ashram. Angered at this, Parashurama killed the king's entire army and, after cutting each one of his thousand arms, the king himself with his axe. As a revenge, the King's sons killed Jamadagni in Parashurama's absence.
Furious at his father's murder, Parashurama killed all sons of Sahasrajuna and their aides. His thirst for revenge unquenched, he went on killing every adult Kshatriya on earth, not once but 21 times, filling five ponds with blood. These are the actions which highlight his warrior characteristics. Ultimately, his grandfather, Richeek Rishi appeared and stopped him. Subsequently, he donated the whole of the earth won from the Kshatriyas to Brahmins. Drona reaped the benefit of this donation by Parashurama; he went to Parashurama and requested for Parashurama's warfare skills. Parashurama agreed.

 Haihaya-Kshatriya Background
It appears that the Haihayas may have been enemies and at war with several groups, including other Kshtriyas themselves. For example the Haihayas sacked Kashi during the reigns of King Haryaswa and King Sudeva (whom they killed), King Divodas and his son Pratarddana (who finally expelled them outside of the Vatsa Kingdom). All these kings were born in the Kingdom of the Ikshvaku, a solar clan and the Haihayas were a lunar clan.
The hostile Haihaya King Arjuna Kartavirya also defeated the Naga Kshatiryas, defeated Karkotaka Naga and made Mahishmati (present day Maheshwar) the capital of his own kingdom.
All the five Haihaya clans called themselves together as Talajangha (Vishnu Purana IV.11).
According to numerous Puranas, the military corporations of the Shakas, Yavanas, Kambojas, Pahlavas and Paradas, known as five hordes (pānca-ganah), had militarily supported the Haihaya and Talajunga Kshatriyas in depriving Ikshvaku King Bahu (the 7th king in descent from Harishchandra) of his Ayodhya kingdom.
A generation later, Bahu's son, Sagara recaptured Ayodhya after totally destroying the Haihaya and Talajangha Kshatriyas in the battle. King Sagara had punished these foreign hordes by changing their hair-styles and turning them into degraded Kshatriyas.

 Extermination of the Haihaya-kshatriya caste

Parashurama is said to have cut off 1,000 of King Kartavirya Arjuna's arms
The enmity between the Haihaya and the Bhargavas are mentioned in the Mahabharata Hindu text numerous times. In the Srimad Bhagavatam SB 9.8.5-6, the Haihaya are mentioned as "the uncivilized"[2].
Once, when Parashurama returned home, he found his mother crying hysterically. When asked why she was crying, she beat her chest 21 times. In a rage, Parashurama vowed to exterminate the world's Haihaya-Kshatriyas 21 times. He killed the entire clan of Kartavirya Arjuna (or Sahasrarjuna), thus conquering the entire earth. He offered his dead father's soul tarpana with the blood of the kings and warriors he slew. He then conducted the Ashvamedha sacrifice, done only by sovereign kings, and gave the entire land he owned to the priests who performed at the yagya, viz. Kashyapa.
Parashurama then became responsible for killing the world's corrupted Haihaya kings and warriors who came to attack him in revenge for the killing of Kartavirya Arjuna, to prevent a Brahmin from being emperor and threatening their position. The Ashvamedha demanded that the kings either submit to Parashurama's imperial position or thwart the sacrifice by defeating him in battle. They did neither and were killed. Parashurama exterminated the world's Haihaya-Kshatriyas 21 times, thus fulfilling his vow.

 Legends
It is said that when Parashurama saved and reclaimed Kerala, he settled Kerala from the retreat of the sea, that was the beginning of the Kollam Era (AD 825) (possibly named after the city Kollam) for the Malayalam Calendar.

According to one legend, Parashurama also went to visit Shiva once but the way was blocked by Ganesha. Parashurama threw the axe at him and Ganesha, knowing it had been given to him by Shiva, allowed it to cut off one of his tusks.
There is an interesting side to Parashurama's conquest of Kshatriyas. After one his conquests, he returns to Aihole (Badami Taluka, Bagalkot district in Karntaka) which, some say was where he lived. Those who know Aihole would know that the river Malaprabha does a near 180 degree turn there. While Parashurama washed his blood soaked axe upriver, beyond the bend, there were village belles washing clothes downriver. The axe was so bloody that it turned the entire river red. This, the women washing clothes saw and exclaimed "Ai hole!" (oh, what a river!). The name stuck and the village is now known as Aihole. There is an another legend that Nairs (Nagas)of Kerala removed their sacred thread and hide in forest to avoid Parasuramas revenge against Kshatriyas. Parasuram donated the land to Nambuthiri Brahimns and Nambuthiris denied the Nairs Kshatriya status (though they did Kshatriya duties and almost all the royal houses in Kerala come from them)

 Shiva's Bow
In the Ramayana, Parashurama came to the betrothal ceremony of the seventh Avatara, Rama, to the princess Sita. As a test of worthiness the suitors were required to lift and string the bow of Shiva, given to the King Janaka by Parshurama. Rama successfully strung the bow, but in the process it broke in two, producing a tremendous noise that reached the ears of Parashurama.
In one such version, played in ramlilas across India, Parshurama arrived after hearing the sound of the bow of Shiva breaking. The kshatriyas were afraid to confront the sage, but Sita approached the sage. He blessed her, saying "Saubhagyawati bhavah", literally meaning "be thou blessed with good luck". So when he turned to confront Rama, the destroyer of Shiva's bow, he could not pick up his axe to do so. This was so because, as he blessed Sita with good luck, he could not cause any harm to her husband. At the same time, he recognised Rama for what he truly was, namely, the avatar of Vishnu as his bow fent flying in the hands of Lord Rama.

 The Mahabharata
In the Mahabharata, Parashurama was the instructor of the warrior Karna, born to a Kshatriya mother but raised as the son of a charioteer, or lower class of Kshatriyas. Karna came to Parashurama after being rejected from the school of Drona, who taught the five Pandava and one hundred Kaurava princes. Parashurama agreed to teach Karna, believing him to not be of Kshatriya birth[citation needed], and gave him the knowledge of the extremely powerful Brahmastra weapon. But an incident would render the Brahmastra almost useless to Karna.
One day, Parashurama was sleeping with his head resting on Karna's thigh, when a beetle crawled up and bit Karna's thigh, boring into it. In spite of the bleeding and the pain, he neither flinched or uttered a cry so that his teacher could continue his rest. However, the blood trickled down, reaching Parashurama and awakening him. Convinced that only a Kshatriya could have borne such pain in silence and that Karna had therefore lied in order to receive instruction, he cursed Karna that his knowledge of the Brahmastra would fail him when he needed it most. Later, during the Kurukshetra war, Karna had a dream at night when he thought of his guru and asked him to take back the curse he had warranted years back. Parashurama explained that he knew that the day would come; he knew that Karna was a Kshatriya[citation needed], but deemed him to be a worthy student and instructed him nevertheless. However, the outcome of the war would have left the world in ruins if Duryodhana were to rule, as opposed to Yudhishthira. For that reason, Parashurama requested that Karna accept the curse and fall at the hands of Arjuna, inadvertently saving the world.[citation needed]
Parashurama was the guru of both Bheeshma (Devavrata) and Dronacharya[citation needed]. Also, the Sudarshan chakra (or Sudarshan Vidya) is said to be given by Parashurama to Krishna.

 The Sixth Avatara
The purpose of the sixth incarnation of Vishnu is considered by religious scholars to be to relieve the earth's burden by exterminating the sinful, destructive and irreligious monarchs that pillaged its resources, and neglected their duties as kings.
Parashurama is of a martial Shraman ascetic. However, unlike all other avatars, Parashurama still lives on earth, even today. Secondly, he is an Avesha Avatara, a secondary type of Avatara. In such an Avatara, Vishnu does not directly descend as do Rama or Krishna but instead enters the soul of a man with His form. Accordingly, unlike Rama and Krishna, Parashurama is not worshipped. But in South India, at the holy place Pajaka, there exists one major temple commemorating Parashurama.
Parshurama, the creator of the Konkan coast, is also worshipped in a temple at Lote Parshurama in Maharashtra's Ratnagiri district.The people of the Konkan call their land 'Parshurama Bhoomi' or the land of Parshurama in accordance with the legend that the sage reclaimed the land from the sea.
There are several Parashurama temples throughout the western coast of India as well as North India, but especially more in the costal areas from Bharuch in the west Indian state of Gujarat right up to Kerala, the southern tip of India. One can see a Parshurama Temple with a Agni Mandir in Shivpuri, Akkalkot, Khopoli in Maharashtra and Fort Songadh in Gujarat.

 Kalki Purana
The Kalki Purana states Parashurama will be the martial guru of Sri Kalki, the 10th and final avatar of Lord Vishnu. It is he who instructs Kalki to perform a long penance to Shiva to receive celestial weaponry.

 Parashurama and Deities' Temples
In the Kanyakumari Temple in Kanyakumari town, Parasurama installed the Idol made of blue stone. Parashurama installed the idol of Dharma Sastha (Ayyappa) on the peak on the Sabarimala Hill in the forest.[1] Parashurama trained Ayyappa[2] just as Parashurama had trained Karna in the Mahabharata and is believed will train the future Kalki.
He created a temple of worship right after he resurfaced Kerala from the sea. He placed statues of various deities in 108 different places and introduced martial arts ("Kalari Payattu") to protect the temple from the evils.[3]
Also, while the other pilgrimages created by Parashurama are devoted to Lord Shiva, Lord Subramanya and Lord Ganesha, Kollur is the only one devoted to goddess Parvati.[4]
There are "Seven Mukti Stalas" of Karnataka, which were created by Parashurama and some of the above such as Kollur belong to them.

 Parashurama Kshetras
eight kshetras are popularly known as Parashurama kshetras and a.k.a. 'Parashurama Srishti'. They are:
Chiplun
Udupi
Subramanya
Kollur
Shankaranarayana
Koteshwara
Kumbasi (Annegudde)
Gokarna