at low player count a poison necro is good but at high player count not really. Bone necro is also weak at high player count, but since this is what you ask, it would look something like :
white in +3 bone spear base
3/20 2os circ with fire facets or um runes
3/10 amulet or 2/10+
enigma
spirit
arach
trangs
sojs
aldurs
9*pnb gc + torch anni and resist+life charms
infinity merc
cast amplify damage on them and as soon as one die use corpse explode