Is satan God's counter-pole. Do darkness and fire belong to satan?
Reality and Scriptures are mono-polar, centered on God. Satan is a creature; a completely different kind of being than the Creator. Satan is not omni-present, not omni-potent and certainly no threat to God.
Darkness and fire, like anything else, belong to God. But Satan hides in darkness lest he incinerates in the Light. To Satan there's a big difference between light and dark. To God there's not (Psalm 139:12).
God wields His fire at His discretion, sometimes to destroy, sometimes to guide, often to purify.
God very often appears in deep darkness (Genesis 1, Genesis 15:17), and not all "bad" things comes from satan: Isaiah 45:7 reads, "I am YHWH and there is no other, the One forming light and creating darkness, causing peace and calamity [the word used here is the common word for evil...!]; I am the Lord who does all these."
After taking all this in account, we may wonder what the function might be of satan. The obvious answer is that he has no function. And perhaps that's why he finds himself shooed off by Jesus as a conclusion of His formative years (Matthew 4:10).
God's empire is like that of bees (the Hebrew word for bee is the feminine version of the masculine 'Word', Logos in Greek; bees have a house, like flowers, make honey, speak a language, care for offspring, are armed).
Satan's 'empire' is like flies (the Hebrew word for fly, 'zebub', comes from the verb 'to zigzag or move around like a headless chicken'. Beelzebub means Lord of the Flies; flies are homeless, like dung and decaying flesh, make nothing, speak no language, don't care for their offspring, are not armed.)