Post is done. Sorry for the delay.
I re-arranged the order of your attacks slightly from the order they were posted in, since keeping it in the exact posted order would have caused some of your attacks to not land and I didn't want to steal anyone's thunder on such a good series of posts. I tried to keep it as close as possible while still making the sequence make sense. I also snuck in a god-mod for Sepher at the beginning.
Ahriman's attacks were as follows:
-Countered Jharm's attack and shoved him backwards. (left the result vague to give Jharm a chance to recover gracefully.)
-Gulgrim's attack on Ahriman also hurt Gulgrim. (leaving it up to you to decide just how hurt, but it should be reasonably on par with the damage Ahriman took.)
-After the soul charge, Ahriman created a big honking wind storm. (This will make it difficult to move and see. You should include how you're defending against or dodging the random lightning in your post or it may hit you.)
-Ahriman is directly attacking the Book of Magnus with an anti-magic spell. (This spell will not be strong enough to harm either the book itself or the Everworld Cloak, given it's artifact status, but will definitely destroy the tesseract and unmake your little mage guy unless someone successfully counters it.)
Let me know if there are questions or if I missed anything.