Short answers, pulled from the story.
Hindu Mahasabha was founded in April 1915 at the Kumbh Mela in Haridwar by Madan Mohan Malaviya, a four-time president of the Indian National Congress and founder of Benaras Hindu University. It began as an umbrella organisation for regional Hindu Sabhas across India.
Hindu Mahasabha promotes Hindutva, a Hindu nationalist ideology developed by its pre-eminent leader Vinayak Damodar Savarkar. The party identifies India as a Hindu Rashtra (Hindu Nation) and believes in the primacy of Hindu culture, religion, and heritage.
Nathuram Godse, who assassinated Mahatma Gandhi on the 30th of January 1948 in New Delhi, was a member of the Hindu Mahasabha. Five co-conspirators were also identified as prominent Mahasabha members, and Savarkar was arrested as a suspected mastermind, though he was released due to lack of evidence.
Hindu Mahasabha officially opposed and boycotted the Quit India Movement of 1942. Savarkar, the party's president, issued a letter titled "Stick to your Posts" instructing members to remain in government and military positions and not to join the movement.
Yes. After Congress ministries resigned in 1939, the Hindu Mahasabha entered coalition governments with the Muslim League in Sindh, the North West Frontier Province, and Bengal. The Sindh coalition, which included Mahasabha ministers, passed the first provincial resolution in favour of creating Pakistan in March 1943.
Hindu Mahasabha won four seats in the first Lok Sabha of 1951 but has declined sharply since, winning no parliamentary seats in most elections after the late 1960s. At the state level it has contested seats in Uttar Pradesh and Karnataka with negligible vote shares and no victories in recent cycles.