義賊、ねずみ小僧を意味するRobin Hoodで資金の出どころに不安を感じますがredress(悪しきを正す)の含みがあり庶民の味方のイメージが強烈です。しかしこれで通じない場合はanonymous benefactor, anonymous donorと言えばいいでしょう。0:01 A mystery donor has been handing out cash-stuffed envelopes to good causes in the northern German city of Braunschweig. The donations have been left at a hospice, a food distribution centre for the poor and other charities. Local media have dubbed the unidentified philanthropist "Robin Hood."
http://www.youtube.com/watch?v=CSvDIqZnjnM 0:46 modern Robin Hood trying to hide the source of his ill-gotten gains.不正な儲けの出所をくらましている現代版のねずみ小僧 2:07 guardian angel 守護神、守護霊、守護天使、、、この言葉にも伊達直人のニュアンスがあります。