Runes:
+4 earth magic (sup + head gear)
+1 energy storage

Basically put everthing up except the item spells and sliver armor.
The idea is to head out to the scareater which is just outside vasburg armoury. (eternal grove exit)

wait for the patrols to settle or go away and then run towards him. You might wanna put up enchantments before that because there are oni nearby.
Use ward of stability whehn fighting with oni.
stand next to the scareater and then put up sliver armor and then vengeful was kanei. USe resilient when the elite is recharging and not on you any more.

You can do this in hardmode.