The most common and most likely answer to this crossword clue is the 4 letter word IAGO
I've seen this crossword clue in Financial Times
I
A
G
O
More clues leading to the result IAGO
- One past Shakespearean villain
- Leader of Italy in the past seen as a villain
- Shakespearean villain one from that time
- One’s taken over a board game -— Othello he couldn’t stand
- Evil character of compiler in the past
- Inhabiting Transylvania, Gothic villain
- Father Christmas almost thrown out of capital as a villain
- Restrained by Portia: gold-digging Shakespearean villain
- Villain making lilac grow evenly?
- Villain, one that’s gone
Buddy explains!
The straight part
We know that "Evil character" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case evil character = iago.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.