Who is the activist investor waging war against Procter & Gamble?

Who is the activist investor who may be about to land a seat on the board of one of Ohio’s biggest employers?

It’s a boardroom battle waged between shareholders wielding blue ballots or proxy cards (in support of Procter & Gamble’s recommended slate of board nominees) and white proxy cards (cast by those who support giving Nelson Peltz a seat on P&G’s board.)