Obtaining a highest fame rating requires that you simply use a character that is of that nature, or by completing skirmishes that reward that type of fame. There is also an option to take jobs from your lord if you're an officer which reward additional fame of different variations. Each of these fames can go as high as fame 9, so you'll have to take part in many battles before unlocking each respective trophy.
It is advised you only do one of these fame choices per playthrough, as there are trophies also tied for seeing endings which are determined by your highest fame.
There aren't many "Kind" Musou officers, however there are a few in the list. It's easiest to create your own officer with the moveset you'd like and simply change his personality to kind. This way, after each battle you're rewarded that type of fame meaning obtaining the highest rank will come with ruling all of the land. If you need some extra, simply play defense battles or donate to your people in order to boost your kindness.