Which religion has the most sectarianism?
All the major religions that I can think of have more than one sect, each espousing its own interpretation of how worship should be conducted, perhaps how the creation unfolded, and what eschatology they believe in.
Buddhism has a limited number of major branches; Theravada (Tantric Buddhism), Mahāyāna, Zen, Pure Land, Tendai and Nichiren. But Theravada (Hīnayāna) alone is further split into some 20 interpretations. There’s Vajrayāna, which includes Tibetan Buddhism and the Japanese Shingon school. Tantric Buddhism boasts numerous sects. And within any one school, differences appear nation to nation and even within one nation, where cultures and tribal histories diverge from one locale to the next.
And don’t even get me started on Hinduism with its huge panoply of gods and goddesses. Major manifestations include; Mahadevi, Durga, Saraswati, Shri-Lakshmi, Parvati, Kali, Mahavidya, Sita, Radha, and Matrikas. But does any other religion match Christianity for sectarianism? Which brand has the greatest choice of flavors?