Unforgotten is an expansion with two dual-faction heroes that worship both Taulot and Kurumo at once, helping you mix red and green heroes together. In gameplay terms, when these heroes take a worship action, you resolve both the green and red worship in any order of your choice. This is the third release of the dual-faction cycle started with Stormsear and Winterdeep.

Unforgotten features a new type of power card with two runes at once that can only be played by heroes with both runes. There are five blue/green and five red/green power cards. The same number of blue/yellow and red/yellow cards will come with Untamed, the last expansion of the dual-faction cycle releasing in 2022.