Dynasty weapons.

a little, a little
now it only absorbs 75% of the damage, not 115% as it did initially
but, it's still an overcorrection.

It absorbs 15 multiplied by the number of creatures in the stack :) In your case, there are 5 of these creatures (15*5=75), in the previous case there were 9 :))))

The bug remains. Moreover, some idiots are figuring out how to use it in duels, and even in Legion mode, apparently they have problems with their heads and hands :)

Added 2 minutes later

You can get 80% for "Drain". If Arachne only gives 15%, no one will use it.

15 isn't that little. The main task of mass drain is to prevent the loss of several dead units from the support group... and the standard drain is applied to the main attack stack. Again, the warrior (and Arachne is a sword, not a staff) sometimes has problems with spell power and mana ;)