Who among the following was known as a Nirguna saint and reformer?

Kabir is widely believed to have become the first disciple of the Bhakti poet-saint Swami Ramananda in Varanasi, known for devotional Vaishnavism with a strong bent to monist Advaita philosophy teaching that God was inside every person, everything. Sant Kabir was known as a Nirguna saint and reformer.