The next big step in FFH. FFH was such a huge project the team had to split it in 4 phases.
Light was the first, it introduced the basic game mechanics, spells, most civs, religions ...
Fire is the current phase, it introduced armaggedon Counter, Infernals and Mercurian civs, and a few other changes.
Shadow is the next phase. It will introduce Svartalfar and Sydar civs, quests (equipment??), probably spying ...
Ice will come last, it will introduce the Illian civ, and scenarios (something like Age of Ice, i read somewhere the team have 18 more scenarios to produce) ...