Zuishin Theodorides ordained and trained under Reverend Ichishima Shōshin, the 36th Abbot of Senzōji, Kangaku, Dai-sōjō and Professor Emeritus at Taishō University.

He started his spiritual quest during his early teenage years. After an exploration of the various traditions represented in Europe, he started practising Pure Land Buddhism under the kind guidance of Reverend Inagaki Zuio, an eminent priest of Jōdo Shin Buddhism and Professor Emeritus at Ryūkoku University.

In October 2015, during a pilgrimage in Japan, he met Ichishima Sensei and converted to Tendai Buddhism, receiving the precepts at the Amidadō of Tamonin.

In October 2019, he once again travelled to Japan. This time, the goal was clear and further aided by the auspicious publication of the Tendai Shido Gyōki in English; it was time to commence his gyō practice and train in the Tendai Esoteric Rituals at Tamonin.

From 30th October to 3rd December, he followed a strict regimen of austerities and ritual service under the direct guidance of Ichishima Sensei. The curriculum included Jūhachidō, Taizōkai, Kongōkai and Goma, as well as Raihaigyō. During his training period, he also studied the Fivefold Transmission of Nembutsu preserved at Senzōji.

Zuishin organises Dharma discussion meetings in Northern Greece and volunteers for Bukkyō Dendō Kyōkai, supplying local libraries, religious centres and interested individuals with copies of the Teaching of the Buddha.