Here's my working model of a villain character sheet. If you can think of any question worth adding, please let me know!
1. What are the character’s strongest traits?
2. What does the character value most?
3. Is the character motivated by winning/competitive streak?
7. Sense of entitlement?
8. Does the character display emotions? Which ones?
9. Would the character take a life?
11. How would the character feel about taking a life?
12. What is the character’s weapon of choice?
14. Does the character “dress the part” of a villain?
15. Why or why not?
16. How did the character’s “villainous” career start?
17. Why did it escalate?
18. What does the character want to gain from his/her villainy?
19. Does the character have any accomplices?
20. Are they equals?
21. Are they his/her master?
22. Are they underlings?
23. Does the character love anyone?
24. Does the character respect anyone?
25. How would the character respond to a physical threat?
26. How would the character respond to an insult?
27. How would the character respond to someone stealing or hurting what is his/hers?
28. How does the character make money?
29. What are the character’s weaknesses/blind spots?
30. How can this character be defeated?
31. Is this character a careful strategist, a blind sheep, or a master of improvisation?
32. Does this character commit crimes of passion?
33. Crimes of malicious intent?
34. Pre-meditated crimes?
35. What does this character secretly long to be?
36. What stops him/her from commiting a crime?