Battle against Karador on impossible

[Arilian]

Finally i made it to Karadot at impossible Difficulty.

I am lvl 18 Mage, about 10-11k Leadeship, and have access to almost all kind of units due sacrifise and some low level pack with ranged units i left behind. I dont have time back (only lvl 1). I can case 2 spell in the first 2 round and have about 100 mana for it with some good desctruction and utility spells. (order and chaos lvl 2, distortion lvl 3)
From the tips hire, i do not have necro call and i do not have royal thorns.


So far it seems i am too weak for this battle. I have avoided almost all elf and undead pack as they are from strong to impossible.

I know i am low level i have also skipped dwarwen and demon pack behind and even some pirate ones. Do i really need to kill all these? (I dont like killing elves )

On what level did you finished with this battle?
Do you think i will NEED time back lvl 5 for this?
I am thinking using Knights with Circle attack talent+Teleport, but i have only access to a few knight so i need to sactifise a good stack for it. (And spend points to circle attack) Have anyone tried it?
Should i be able to get Dryads and Royal thorns withough doing any quest in the elven lands? I did not find any.

Thanks for all your help.