Can there be bad angels wandering about working for God

Can it be possible there exists bad angels wandering about, but who are on God's side and work for Him?

It's an interesting theory that involves mythology. The essential Judeo-Christian-Islamic belief upholds an absolute good God and his angel minions are all good beings.

Given the presumption that angels were created with their own version of free will and are extremely intelligent, every angel at the dawn of the creation of the Universe had to decide for itself to worship and obey God for eternity, or to turn away from Him.

According to Judeo-Christian-Islamic mythology, many angels were proud and rejected the purpose of their creation - to worship and serve God. They wanted more and became disenchanted. These discontented angels rallied around their chosen leader, Lucifer, the most disgruntled seraphim angel of all. The angels quickly split into two groups, loyal to God, and those unwilling to follow God and therefore in rebellion. One possible theory is that there existed angels who felt discontented as well but decided to remain loyal to God. These angels may have sympathized with Lucifer and his followers, but they chose ultimately to side with God, perhaps out of fear of God, and those who accurately reasoned that Lucifer and his followers stood no chance of winning. More, there could have been fence-sitter angels, those who chose to remain 'neutral', waiting to see who would win. God would later treat the fence-sitting angels as disobedient and punish them as well.

So in the end Heaven is populated by God and his loyal angels. Loyal doesn't necessarily entail, 'good', in the sense that we humans are used to assuming. That means there might exist angels who are not friendly to humans but themselves are not confined to hell but are still allowed access to Heaven. It's not known if God would have punished loyal angels who may have harbored politically incorrect thoughts or even spoke their mind. More likely, if these unhappy angels did their part and fought earnestly against the rebellious angels, then God kept all loyal angels in Heaven.

Don't forget the mythology where God endows 200 angels with humanly bodies to watch and assist early man. These angels did not rebel against God, but incurred His displeasure and wrath by doing something not approved of, copulating with human females. Moreover, these angels reportedly started teaching human males and females certain skills and knowledges that God had not told them it was okay to do so. In the strict relationship between God and angels, disobeying orders and instructions; exceeding one's orders or authority; are all construed as rebellion and treated harshly by God.

So if the theory is correct, it does not bode well for us humans. That means there's effectively hostile angels about that could and would hurt humans if given the chance. For humans these would be 'bad' angels who are not confined to hell but enjoy freedom of movement as their 'goodly' angel brethren. Only their fear of God keeps them in check. The presence of 'good' loyal angels keeping an eye on their less reliable angelic comrades helps keep those guys on the straight and narrow. A heretofore loyal angel who harms humans - without God's orders or permission - is reclassified as a fallen angel and is subject to punishment that makes one a demon or devil. These guys don't want to go hell, no more so than we humans. So it still all works out.