What is the ruling on working in a place where there are combat games that are forbidden by Sharia, and I am asked to make accounts for their sale and purchase, and do I bear sin for that, and what should I do regarding obeying my father in this matter given my fear of his reaction?

If the game is permissible, and the method of acquiring it is permissible, and it does not lead to the neglect of obligations such as prayer, then there is no harm in creating accounts for it.

However, if the game is forbidden, or will lead to something forbidden, then it is not permissible to create accounts for it; because that would be assisting in something forbidden, as Allah Almighty says: "And do not cooperate in sin and aggression."

And if the games are forbidden, then it is not obligatory to obey the father in creating the accounts; for there is no obedience to a creature in disobedience to the Creator, as the Prophet (peace be upon him) said: "There is no obedience to a human in disobedience to Allah."

Disobeying the father in something forbidden does not cause harm, but one must be gentle in apologizing to him and show good manners.