Bhai Bachchitter singh were five Khalsa brothers. The Eldest was bhai Udai Singh, second Ajaab Singh third Aajaib Singh, Ajai Singh and Bachchitter Singh. They were sons of Bhai Mania, who was a descendant of a Rajput named Mai Das residing at the village alipur in district Multan. Mai Das had abandoned the Vaishnav beliefs during the times of Guru Amardas (third guru) becoming his Sikh. He was also given a Manji (village alipur) at his village by Guru Amardas. Since then all of his generations regularly contacted the Sikh gurus of their respective times affirming their beliefs.
Bhai Mania when came in to visit Guru Gobind Singh at 1692 he offered all of his five Sons for his service. At the same time (year 1692) Bhai Nand Lal of Multan also first contacted Guru Gobind Singh when he visited Anandpur sahib. These five brothers (sons of Bhai Mania) lived along with other Gur Sikhs at Anandpur sahib getting trained in martial arts as well as education. Then in 1699 on the visakhi day when Khalsa was born, all the five brothers along with their father Bhai Mania became Khalsa by taking the Khanda Baate da Pahul. After Amrit, Bhai Mania became http://www.sikh-history.com/sikhhist/martyrs/mani.html">Bhai Mani Singh and then he became a famous Martyr (Shaheed) Bhai Mani Singh of Darbar Sahib.
All the five brothers lived and helped Guru Gobind Singh while Bhai Mani Singh was sent by Guru Gobing Singh to make copies of Adi Granth and to install them all over Punjab. These five brothers participated in all battles fought by Guru Gobind Singh against the Hill kingdoms around Anandpur Sahib.
Bachchitter Singh is famous for his exceptional valour in the second battle fought at Anandpur Sahib. He alone fought a drunken elephant let loose by the enemies to break open the gates of the fort at Anandpur sahib. In the year 1701, the king of the Gujjars named Jamtula at the request of Bheem Chand attacked Anandpur Sahib then Sikhs named Bhai Bachchitter Singh Bhai Alam Singh Bhai Daya Singh faced him and defeated him.
Jamtula and Bheem Chand seeing that they could not enter Anandpur Sahib decided to lay siege of the fort with emphasis being on cutting supplies to the Guru Gobind Singh, his family army. Guru Gobind Singh had planned these forts around Anandpur sahib with keeping water and supplies in mind, the biggest of these forts was called Lohgarh (iron fort). So, After a month or so of siege Bheem Chand seeing that Guru is not bulging became restless for an alternative means. They decided to let loose a drunken elephant at the main enterance of the Lohgarh fort to break its steel doors. Bheem Chand's friend from villge Jaswalia named Kesari chand swore that he will enter the fort of Lohgar at all costs.
To face this threat, Guru Gobind Singh himself prepared Bhai Bachchittar Singh presenting him with a spear named "Nagini"., he and two other Singhs was sent to battle among the war cries of Sat Sri Akal. This spear that is named Nagini still exists at the gurdwara Takht Keshgarh Sahib at Anandpur Sahib. Historians recall that Bhai Bachchittar singh along with two other Sikhs came out of the Lohgarh fort riding on their horses. Bhai Bachchittar Singh galloped straight to this drunk elephant and threw the spear with such a force between the eyes that it pierced through the armour as well as bones of the elephant. Severely wounded this elephnat turned around on the forces of Bheem Chand and Kesari Chand. The driver of the elephant (Mahaut) fell down and it crushed many of the soldiers of Bheem chand and Kesari chand. Just then the rest of the Sikh army came out of the fort of Lohgarh and started pursuing the enemies. Both Bheem Chand and Kesari Chand were wounded in this battle. But this battle was undoubtbly Bhai Bachchittar Singh's battle.