Hammers and BOne Type Necros are Magical damage, hence why they are some of the most new characters around. Every character has a counter set up except these two classes. You can not reduce or absorb their damage be a efficent amount thats why it is so easy to win with these type of characters.
Thats why when i kill necros and they say I HAVE NO DR YOU SHOULD WIN, i just say i haven o Magic Damage reduction you should win. They do 6.5k+ Spirit and Spear and i do 6.3k MAX with Guided arrow and my min damage is 533 while there min is like 6.2.