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You shouldn't mention anything about Paganism or anything that will trigger his violent Muslim instincts. Just say you are not really religious and don't care to think about it. It is kind of hard to backtrack on the "multiple Gods" comment, but I would try to just overshadow it with general apathy and extend this to Islam. This is much easier to defend than to "admit" that spirituality exists.
Yes, you do not want him to pray for you, or any other aggressive actions where he tries to influence you, for that matter. Honestly, you should stick up to him and tell him that his obsession with changing your beliefs makes you uncomfortable and not want to be around him. If you feel nervous about this, then quickly breath in fire energy and affirm it has positively allowed you to stick up for yourself.
Simply keeping clean and having a strong AOP will defend against most of any damage here. Doing the rituals of the Gods, or at least meditating on their sigil, will allow you to keep a strong connection with them.
However, if this situation goes too far, you can raise Ansuz energy and program it to remove this negative situation of him inappropriately getting close to you. As you said, making money is good, but being attacked for your beliefs is and. Therefore, focus energy on removing the negatives of the situation. This represents more of a permanent solution, although it takes time and energy.
In a worst case scenario, you can take a more aggressive approach and use Thurisaz to destroy any non-professional attachments from him soul to yours. Note that this may have to be repeated if you are around him, but it is better than nothing.
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No, Satan is not mad at you, because you did not ask for this. However, you need to be aware of the situation and know that being around negative people will influence you negatively, unless you take steps against this. Those who are more independent may fare better, but please do not assume you are invincible here.
The energies of relationships go both ways, as shown by the Gebo rune. Yet, one person can attempt to dominate the other and upset the fairness of a healthy relationship. Energy flows between souls, and therefore you don't want him to subconsciously change your opinions.
No, you should not "infiltrate" the Muslim community, as I don't believe this is your duty, and it would come with many risks. Zevists are best off advancing and doing warfare in secret and in safety, not surrounded by crazy people. There is no need to get close with them for any reason.
This is something you need to discuss with your GD, as it is a matter of personal safety, and you have to weigh all the factors. Maybe it is not energy efficient to try and fight this, therefore you should leave. These type of questions can be answered by your GD, who knows the situation better than anyone here.
Just be aware to not take this situation lightly, especially as this Muslim is showing an intent to dominate you. Even if you win against him, it will still require an input of energy. No fight is without a cost.