Yes, a Pagan can become a theistic Satanist. In practice, the transition can look very different from conversion out of an atheistic or strictly monotheistic worldview.
Many Pagan traditions already make room for ritual, offerings, spirits, gods, sacred space, seasonal practice, and personal devotion. The question is therefore not simply whether spiritual beings are real. It is what place Satan will occupy in the person's religious life.
“Pagan” covers too much for one conversion story
Heathenry, Wicca, Hellenic religion, Druidry, eclectic Paganism, reconstructionist traditions, and personal polytheism do not share one theology. Some people worship several gods; some work with spirits; some use ritual symbolically; some combine traditions.
Any article claiming there is one standard Pagan-to-Satanist path is already oversimplifying.
The central change is devotional orientation
In this Church, Satan is not added merely as another aesthetic or occult interest. He is approached as a real spiritual being and the central figure of the Church's worship.
That does not automatically answer whether a person can continue venerating other deities or spirits. Individual members may hold different views, and the wider theistic Satanist field is even more diverse. What matters is being honest about the commitments you are actually making.
You may keep more than you expect
Ritual habits, meditation, altar work, offerings, journaling, study of historical sources, and respect for religious plurality can carry over naturally. A conversion does not have to erase every useful discipline learned elsewhere.
At the same time, familiar practices may take on different meanings when the theology changes. An altar is not defined by its furniture; it is defined by what relationship the practice is serving.
Avoid collecting identities
Modern online spirituality can reward accumulating labels, pantheons, symbols, and initiations faster than a person develops a coherent practice. If you are considering theistic Satanism, it is worth asking whether Satan has become genuinely central or simply newly interesting.
There is no prize for deciding quickly. Spend enough time with the practice for novelty to wear off.
You can remain Pagan
Exploring Satanism does not create an obligation to convert. Some Pagans will conclude that Satan fits into their existing religion without changing their identity. Others will decide theistic Satanism does not fit at all.
The Church can explain its own theology. It should not decide another person's religious identity for them.