This was on the front page of DA a little while ago.
Let's go for William again.
MARY SUE TEST Is you OC a Mary Sue? The test works for most of canons.
If your answer to the following questions is "YES" add yourself the points. 1. Does your character have unnatural hair color? (dyed hair does not count) +2
Nope2. Did your characters hair/eyes changed color over time on their own? +4
3. Does your character have any super/unnatural powers? +2 If it's a canon where many character have powers, are your character's stronger then most of the others'?
Nope4. Does your character have two or more people romantically interested in them? +2
5. Does you character have love interests in two or more people? +1
6. Your character's past is:
a) Tragic, traumatic +3
Yesb) Mysterious, unknown +4
Nopec) Regular +0
7. Was your character technically dead and then it managed to come back to life? +5
8. Does your OC become the main character of the canon once it's there? +6
Wait... so if your character in the main character you get mary sue points? This doesn't make sense. Or am I not understanding this question? *Huge Confusion*
9. Can your character fight down the stronger enemies? +4
10. Does your character have it's own nemesis or somebody powerful after them? +4
11. Did your character kill anyone? +1
Yes, but he was a soldier, so...
12. Did your character save somebody's life? +1
13. Does your character have unnatural features? (Like cat tail, animal ears, some claws or such) +1 point for every feature
Unnatural? No. He is an animal, though... I'm gonna go with no.
14. Is your character a mix of races? (Vampire, mutant, werewolf, fairy etc.) +1 point for every race
15. Does two (or more) organizations fight to get your OC jon them? +3 I may think of more questions later.
11 if being a main character counts as Mary Sue (#8)
TOTAL: 0-10 You'd rather travel to the moon and back again than create a Mary Sue on purpose
11-20 Your OC is an interesting character with no overdose
21-30 Your OC is acceptable, but maybe you could fix some things
31-40+ Too bad. You created a Mary Sue, face it.
Feel free to copy+paste or take the test in the comments.