Question: if i wanted my hero to do 0 damage but still be able to attack, could I use critical strike and set the damage multiplier to 0 and the percentage chance to 100%?
yes you can use critical strike but with negative values and not 0 (0 means no effect)
but you can also do it without critical strike just set the damage base of your unit to a negative value like -99999 and your unit will deal 0.00 damage.
Ghan has said he has fixed this. Monovertex please confirm this fix. This was only a problem with people that had signatures in the upper levels like not the special members but the respected members.