What do you mean by "unicode", then? By itself, Unicode is a correspondence between characters (i.e. "Ы", CYRILLIC CAPITAL LETTER YERU) and integers (in this case, 0x042B or 1067), except unlike ASCII or other single-byte encodings, the integers aren't limited to the range of [0, 255]. Do you need to transform the UTF-8-encoded text into an array of integers? In order to represent Unicode code points as bytes, you need a Unicode encoding; UTF-8, UTF-16, UCS-2BE are all examples of those.

Perl has a native representation for Unicode code points, which it calls wide characters: for Perl programs, they are like bytes, but have values above 255 and are interpreted according to Unicode rules. Since files and input/output streams contain bytes, not Unicode wide characters, there needs to be an additional encoding layer between them and Unicode. Which is why it's important to read at least perlunitut before attempting to work with Unicode in Perl.