Here we are with another one!
The question basically boils down to:
What is the damage that is dealt out by Ten Numb.
Now, we know that Biggs (and consequently, gallant Haven) will not work against Mauler Mithel. I contend this is because there are two parts to their Triggers... The first is "Suffers Damage", and the other is "During an Attack"...
Now, we all agree they Suffer Damage. They're not Dealt Damage, they Suffer Damage... That wording satisfies the first part of the Trigger, Suffering Damage.
however... It is during a Move... Engageing... Not during an attack...
Which brings us to Ten Numb...
HIS activation is "While Attacking"...
Would not "While Attacking" suffice a "during an attack" trigger?