The 24 character strengths are accessible to all. In KS2 most of the strength words can be understood by the children. The cards I created include a child friendly definition of each one. However, teaching the children about the character strengths is much deeper than just learning the vocabulary which is why it is important to also begin teaching them about the virtues as they get a little older. Character education is just that; strengthening and nurturing character and virtue.
To introduce more about the virtues to the children, I would recommend the children try and sort the strengths into the correct categories; Humanity, Temperance, Courage, Wisdom, Transcendence and Justice. Most card packs you find have some little clues such as color coding and symbols. By sorting the strengths into the correct virtue category so many discussions can begin. It may even be a nice enquiry project for older children during Personal Learning time.