1.You can use hit & run tactic.
2.If you have some skillpoints you can learn METEORSTRIKE and burn them easy like a candy from a baby <img src="/ubbthreads/images/graemlins/evilgrin1.gif" alt="" />
3.You can kill them later first open those tombs and run to level 4 P.S but in lv4and5 there will be a lot of (guardians,conjuqers and also minions) then you kill the necromancer in final catacombs level kill his all servants dont run to MARDANEUS like a kid.