if you need a rare like Ellena’s necklace, do you need to farm her on elite or ultimate? or will she still drop it on normal
She will of course drop it on normal, but if your level is significantly higher than hers than the drop rate would be very low. Also, it’s better to farm the highest level you can manage so that the drop is higher level version.
but its only a green item. i dont need to wear it, just need it as a crafting ingredient
There is a tool tip that tells you that mobs which are significantly lower than you do not drop certain items. I would farm at the highest level that you are capable of doing so efficiently.
Also bare in mind that some items can be bought (ie. green Troll Club) from special merchants.