I didn't try out hardcore - but tactical is more difficult than "easy". At easy I had only a maximum of 4 randomly summoned creatures in the end fight - at tactical I had 7 or 8. (spider, Lizard King, Black Bishop, Earth Elemental, Shadow Creature, Warlock, Chaos Creature and a skeleton?, not sure about the last)
I played tactical due to a clicking error - and only realised this in Act 3, when I kept on dying and despaired at my non-existant combat skills. Serrick's Island had about 8-9 Earth elementals at the same time wanting my blood - at easy, I had a max of 4.
I had no Necromancer in my end fight on tactical - but I don't know if due to randomness or difficulty settings.
If you have already killed Damian at hardcore with a different tactic => Hammer stuns, but gives a low bone damage. I found it more effective to stun and then use melee on him in alternating terms. Fireball at 5 and sneak was very effective - I shot 2 balls, moved a bit in sneak mode - drank mana - shot 2x again etc. I think, I only needed 10-15 mana potions and no health. I had 900 mana as you had, my char was a mix.
Grmbl, I changed my slider to hardcore => I only had a spider, critter, Warlock, Earth Elemental, nothing else <img src="/ubbthreads/images/graemlins/puppyeyes.gif" alt="" /> - used shield blocking on 5, 1-hand+shield and Hammer on 4. As I was only lvl 29, you can imagine, how many skill pts I put into 1-hand+shield (about 25?) - used about 10 HP and 10-15 mana, not sure, maybe less.
I didn't attack the summoned, just used hammer on the DK to stun him - and this spell killed the other creatures by and by.
