1. If the reincarnation of Lancelot du Lac demands that I give him a sword, I will say 'no.'
a) Even if he challenges me to one-on-one combat.
b) Even if he says I have no honor.
c) Even if he calls me a coward.
(See #40 of the Evil Overlord List: "I will be neither chivalrous nor sporting. If I have an unstoppable superweapon, I will use it as early and as often as possible instead of keeping it in reserve" and #44: "I will only employ bounty hunters who work for money. Those who work for the pleasure of the hunt tend to do dumb things like even the odds to give the other guy a sporting chance")
Interestingly enough, though not evil, Percival seems to be following Evil Overlord Rule #4: "Shooting is not too good for my enemies."
Now that I've had some time to think on it, Morgan le Fay is the one who seems to be really paying attention to the Evil Overlord List. For example:
1. Shooting is not too good for my enemies.
2. I will not gloat over my enemies' predicament before killing them.
3. I will be secure in my superiority. Therefore, I will feel no need to prove it by leaving clues in the form of riddles or leaving my weaker enemies alive to show they pose no threat.
4. I will be neither chivalrous nor sporting. If I have an unstoppable superweapon, I will use it as early and as often as possible instead of keeping it in reserve.
5. If I learn that a callow youth has begun a quest to destroy me, I will slay him while he is still a callow youth instead of waiting for him to mature.
6. I will instruct my Legions of Terror to attack the hero en masse, instead of standing around waiting while members break off and attack one or two at a time.