But Don't you think that if author name start with I , V , M ,etc then it will remove that letter from that name. and author name will be change.

Why wonder about that if you can simply try?

As \w Match a "word" character , \d Match a decimal digit character, i want to know is there any special character for roman number also

Even if it existed it would only help you if the roman numerals were written with special character, for example Ⅰ U+2160 ROMAN NUMERAL ONE instead of I U+0049 LATIN CAPITAL LETTER I