None. It's just a legend that STR increases crt rate of skills. In Awakening servers you had to increase STR for skill mastery on daggers/archers and DEX for crt rate of skills BECAUSE we had passive skills that gave it as effect. Also in awakening server you had STR giving p.atk AND critical damage. Which is not working on this server as this server is built on Classic version (which seems to work more or less as High Five). You can test it urself: get a char lv 40, make it use 50 skills with normal stat. Then go +12 STR with dyes and after -15 STR and see the difference in skill critical rate. Most likely, you will see no difference between +12 and -15, and if you do it's not like you crt 10 skills with -15 and 40 skills with +12.
