Karalis is rather of Turkish origin.
Very common for modern Greek surnames since large areas
of the Greek-speaking space (Asia Minor and todays Greece)
were under the Turkish rule for centuries.
"Kara" in Turkish (or Arabic?) is "Black". Thus, "Karalis"
is "Black Ali" (the final "s" is common end in greek; usually
for masculine names).
See about the meaning of "Ali" in the main database:
http://www.behindthename.com/nm/a2.html