I have to agree with Marius there.
I do not believe that Valkia's ability work like the Toughness keyword like some posters seemed to think. Her ability should kick in AFTER damage is applied since the card text does NOT say "move any number of damage assigned to or on this unit," but rather "move any number of damage on this unit." Damage tokens are simply placed beside a target card when they are first assigned (page 12 of rulebook: Damage tokens are placed near the card(s) to which the damage is being assigned...). This means damage tokens are not yet placed on the card during assignment of damage step. Now the Toughness keyword on page 16 refers to: the Toughness keyword cancels its numeric value of that damage BEFORE the damage is applied. This cancellation of damage happens in between the steps of assignment and application of damage. Valkia's ability however is an action. Actions can be taken at the end of each of the 5 steps in the Battlefield Phase, which includes steps when damage is assigned and after damage is applied. However, Valkia's text saying "damage on this unit" implies that damage has been applied already and placed on the unit. Therefore this action cannot come as a cancellation interrupt like Toughness.
What I'm saying here in a longwinded way is that: her ability is an action that triggers after damage is placed on her, which is the latter part of step 5 of Battlefield Phase and it is certainly not a cancellation like the Toughness keyword, which occurs between step 4 and step 5.
If this interpretation is true, then most will ignore her when there are corrupted units lying around, unless one can deal enough damage to take care of her permanently. Which still makes her interesting if there are ways to block some damage (preventing a kill) or transfer damage from allies.