Last month, the board of directors urged shareholders to decline the report.
CEO Bobby Kotick's decision comes as Microsoft faces continued scrutiny over its bid to acquire Activision Blizzard
The family previously brought a suit against the company in March.
Martinez's role will involve revamping the culture at Blizzard as the company seeks to course-correct following last year's sexual harassment scandal.
Shareholder groups are demanding records of the company's deal with Microsoft in an effort to gauge the fairness of the valuation.
"We believe the proposal is neither necessary nor in the best interests of our Company or our shareholders," the board said.
The outspoken investment group claims "Microsoft's offer fails to properly value Activision."
Two top lawyers are no longer involved in the case.
The appointment of Hines comes amid a host of legal troubles for the embattled company.