Please find below a list of K adjectives which might be used to describe a person.
Positive
kind
kinder
kindest
kindhearted
knowledgeable
Negative
knavish
kooky
Other
kinky
There are many more lists of adjectives on this website. For more adjectives starting in K, see this post containing a large number of adjectives beginning with the letter K, some of which can be used for describing people.
known