Every faction in Endless Legend [official site] feels like it required as much playtesting and balancing as some entire strategy games. There are eight major factions in all, from the Necrophages, who devour those they meet rather than engaging in diplomacy, to the Cultists of the Eternal End who cannot create new settlements of their own but can convert those that they conquer.
Amplitude have just announced an expansion, Endless Legend: Shadows, that adds a new faction - The Forgotten. They're experts in espionage but the new spying and stealth features will be available to other factions as well.
Amplitude have some of the prettiest art in the business so new trailers are always welcome.
There aren't many details about The Forgotten yet, other than what you hear in the video, but Amplitude have released information about the major features of the expansion.
Play the brand new faction, the Forgotten, expert in the new espionage skills
Play with invisible units using the new “Camouflage” and “Stealth” capacities
Infiltrate an empire to steal, capture and sabotage
Pillage villages, extractors and watchtowers to slow your enemy’s progression
Equip your heroes with “Scope” accessories to give them special espionage abilities
Defend yourself by using counter-espionage skills and the new “Detection” capacity
We chose Amplitude's strategy masterpiece as our favourite game of 2014 and will be meeting with members of the team at Gamescom in a couple of weeks to find out what else they're working on.