That game was Iron Throne (a mobile game). A bit of a warning, Iron Throne is a real time game that is heavily reliant on Alliances. You have a base where all your resources are kept. If you're attacked, not can your troops be killed and all your hard earned resources be stolen, your heroes can be executed. Attacks are coordinated real time. Meaning other alliance members can a.s.sist you in attacking a base. The only real way to stop a coordinated attack is with a coordinated defense. And that's why alliances are key.

Great experience but very time demanding if you are in a top alliance. Lots and lots of destruction and conquering. Haven't played it in almost 2 years, so it might have changed a lot.