You post actually give me a idea how the things could play out.
King vs Zoro continue, Zoro manage to cut down King with ashura)>King awakening, he cut down Zoro and break sandai, Zoro falling down. Hitetsu sees Zoro, meanwhile King going rampagne and put whole flower capital in flames(like the great fire in tokyo).
Hitetsu fuse broken Sandai+Nidai and make it to a ultimate good sword, Zoro slowly stand up again(get informations about the previous ringo daimyo and also we finally see Ryuma flashback), meanwhile King stomp few other important characters. Zoro use a high new class attack to jump into the sky and reach Onigashima.
Final clash with King vs Zoro and a big CoC clash and perhaps Zoro awake finally one of his sword into black blade and defeat King and cut off all the flames around flower capital.
Sandai doesn´t must been in hardening, but if King actually broke it in hardening, I going to wank him even more :).