SEATTLE — Mark Driscoll has long been an evangelical bad boy, a gifted orator and charismatic leader who built one of the nation’s most influential megachurches despite, or perhaps fueled by, a foul mouth, a sharp temper and frank talk about sex.

The church he founded, Mars Hill, enjoyed rapid growth in the Pacific Northwest — one of the most secular regions of the nation — and it claims 15,000 members worshiping at 15 campuses in five Western states, and 200,000 more people watching its services online every week. Mr. Driscoll became a celebrity in conservative Christianity, a sought-after speaker and prolific author known for a celebration of masculinity that helped Mars Hill attract young men, a demographic noted in church life mostly for its absence.

But now Mr. Driscoll’s empire appears to be imploding. He has been accused of creating a culture of fear at the church, of plagiarizing, of inappropriately using church funds and of consolidating power to such a degree that it has become difficult for anyone to challenge or even question him. A flood of former Mars Hill staff members and congregants have come forward, primarily on the Internet but also at a protest in front of the church, to share stories of what they describe as bullying or “spiritual abuse,” and 21 former pastors have filed a formal complaint in which they call for Mr. Driscoll’s removal as the church’s leader.