As for Creek, it should be capitalized. As per the Native American tribes treaties with the U.S., they are all sovereign nations as well as population groups. They have their own website. Different tribes have different denominations within them. The Creek Nation of Oklahoma is the Muscogee...
Meaning, if God wills it. Used like the Islamic in'shallah, Deo Volente was a common saying in the Middle Ages. Came to be referred as sub conditione Jacobi in Latin. Connected to Deus Vult, common crusader battle cry. Deo Volente- if God wills it Deus Vult- God wills it