Some of the 'Sufi' teachings of the past, even if they looked Islamic on the front, were actually studying Satanic teachings. They were assisted by Lord Asmodeus himself. We don't know what some of these 'Sufi Teachings' of the past were and that information cannot be disclosed, but what is called Sufism today is not Satanic. It could be called 'Islamic Gnosticism', which reminds me of Buddhism teachings at some point. The concept of 'killing the ego' is also present in Sufism, for which they do absurd things like stabbing themselves with iron skewers and walking on fire.