Blind the archon, flee, and reengage. Works wonders because the conjurer is busy trying to cancel the blindness. Only Maelifarau ever used to do it though from what I recall. If you don't, you'll not be able to do much to the conjurer.

To have a fighting chance of pulling this off, I think you need to be a hero though, when fighting heroes.

Regarding version2 of spellbane, what do villagers and warlocks have in common? Makes sense that they'd have a power in common, to the extent that it works against necro spells.