Why does Will Scott pledge his loyalty to Francis' cause in the novel, The Game of Kings?

Will appreciates Francis' sense of loyalty and seeming straight-forwardness. Francis does not play the political game popular with others, nor does he practice hypocrisy. He states his intentions and follows through without wavering. Will finds these traits to be admirable in a leader and lacking in Scotland's armed forces, so he pledges his loyalty to Francis, and in return, Francis becomes Will's mentor.