We just beat Nyarlathothep in the final battle, which was our first final battle. Woohoo! Two players, so we needed 22 hits on the elder one to banish it. During a few turns, we adjusted our characters to have the maximum amount of fight and lore skills. We were lucky to have 5 clue tokens each at the start of the battle, I only lost one during the whole fight. You're immediately devoured if you don't have any clues when Nyarlathothep attacks. I was lucky enough to have Professor Armitage as an ally, he removed Nyarlathothep's magical resistance when I attacked him. The fight felt easy, so I began to wonder if we did everything correctly during the fight. We traded items during upkeep which was allowed. I had two bullwhips to re-roll two of my combat check dice each turn. My brother gave his shrivelling spell to me when he was down to 1 sanity, I could use it to full effect (because of the professor).
Where I think we went wrong is with casting spells. If I cast Shrivelling during final battle upkeep, does the effect last long enough for me to add the 6 dice to my attack?
Here's the card text:
Shrivelling
Casting Modifier: -1
Sanity Cost: 1
Any Phase: Cast and exhaust to gain +6 to Combat checks until the end of this combat.
Having read it again, I guess I should have used one hand when attacking the elder one to cast the spell… it didn't do a huge difference, I only used a bullwhip in my other hand so I would have attacked with one less combat die per turn.