User blog comment:Master Sima Yi/Assassinews 05-08-'14 – Assassin's Creed: Rogue announced/@comment-25344053-20141106180850/@comment-3046679-20141106211113

That never got explained either, and was done more for gameplay purposes than anything else. "Here, have two blades, son. Nevermind we give out two to Master Assassins only, or at least we've used to."