I made a small modification with a necklace artifact: Shadow Sect Medallion. It adds resistance to the slow for our units. The graphics was ripped from Might and Magic VIII (http://mightandmagic.heroes.net.pl/mm8/items/miscellanous/amulet_04.gif).
Download: https://drive.google.com/open?id=1oOAAGts8Fjpa5WO4LqdN3ZliQJ2c0IE-