Our overlord says that we cannot spend movement on his turn. So if we interupt him on a guard i cannot spend a fatigue for cleaving cause that means your spending movement on the overloards turn..

Is this true? I thought the ability says you may spend 1 fatigue regardless of whos turn it is.

According to the FAQ, a Guard attack is subject to all normal attack rules and the hero has access to all skills and abilities connected with that. So yes, (even multiple) Cleaving on a Guard attack is perfectly legal.

Spending fatigue is completely different than spending movement points. Fatigue can be spent to gain extra movement points, but that is just one way to use fatigue. (When you spend fatigue to add dice to an attack, does your OL imagine that the fatigue is converted to MP and then the MP are spent on the attack? If so, a hero would be able to use MP to add dice, which is not the case at all.)

The specific case of Cleave is actually in the FAQ:

Q: When making an attack with the Guard order, can a hero use abilities such as Cleave that grant extra attacks? What about other special abilities?
A: When making a Guard attack, a hero retains access to all appropriate special abilities unless otherwise indicated. This includes abilities such as Cleave, Quick Casting, and Rapid Fire that may grant an extra attack.

(Parathion was quicker than I, but I already typed this, so I'm hitting "Publish" anyway.)

Idontunderstand said:

On a related note, your OL is wrong about not being able to spend movement point on his turn as well. That is basically the hero Tahlia's power. Now granted, you don't normally receive movement points during the OL's turn and you can't spend fatigue for movement points during the OL's turn but Tahlia is allowed to spend the movement points for any type of movement action.