first off gangel wont do anything cmastery > it, as a necro u should learn how to play defensively with it and u will make a sorc sweat trying to get close to u, learn how ibs works, gear wise try using a 4 thul'ed armor (depending on master lvl) only way i see to help reduce damg, if all fails use a druid 2x rfrost + earth spirit thus nullfying all damg from any cold attack lolz