This review is for ranked and has no ideas mentioned about conquest or bifrost game modes;
Very OP clan at the late game that gets an exponentially better economy which pairs even better with your allies. 10/10 really good concept and well made idea.
What I like;
Duchy's are so OP, however they will not play off in the early game due to the production Nerf.
One of the best clans for support; pairs well with your allies in that you can support them mid game and give them heavy bonuses. With clan of the owl on your team, you can get relations really fast and trade for lots of money (which surprisingly makes up a lot of your income if you go this route).
Pray to the stones; who needs faith buildings when your the most powerful clan at faith in the early game. Unless you want to forge a relic or go the fame route, I wouldn't recommend even making a monastery.
Sentry spamming; if you're playing with tanker clans you can make a "dps bomb" by making 30+ sentries in 803 that deal area of effect damage and can shred most troops if they aren't in the front lines.
What I don't like;
Very weak clan against rushers don't even think about it
Their military is much weaker than lion because of how infrequent their military upgrades trigger, military levies can help offset this if you play the clan good enough.