The greatest Kushana ruler whose contribution to Buddhism was even greater than that of Ashoka, was

Kanishka, A descendant of Kujula Kadphises - founder of the Kushan empire - Kanishka came to rule an empire in Bactria extending from Turfan in the Tarim Basin to Pataliputra on the Gangetic plain. The main capital of his empire was located at Puruṣapura in Gandhara, with another major capital at Kapisa. He was the greatest Kushana ruler whose contribution to Buddhism was even greater than that of Ashoka.