I have to keep reminding people, that this entire war was orchestrated by Law. He's the one who held up Kinemon/Momonosuke in PH until Luffy arrived, the one who made the "30% success" comment and took down the SMILEs. He's also the one who got them all to Zou, because of Beppo, where the alliance was formed.
Wano will also see Kid added to form the "Terrible Trio" formed since Sabaody. If you think Oda formed this trio for no fucking reason, you clearly have not been paying attention
So no, there is no room for a 4th actor here against Kaido. I think Zoro's role was hinted at in Dressrosa. Just like he fought an Admiral swordsman in DR, he will fight a Yonko swordsman in Wano.
But that won't be his "main" fight. His main fight is either Queen or King (that's not the end of it). Oda is recreating the "run to the top" scene here like he did in DR. Luffy/Law march to the top to fight boss while Zoro clears the obstacles (Pica). Here it will be a Calamity instead of a Seat, but afterwards Zoro helped with the birdcage. It wasn't JUST beating Pica.
Remember, the point of the commanders is to clear obstacles for the boss. Look at Jozu and Whitebeard.
Look at what Luffy says
Oda is emphasizing over and over and over and over, that Sanji, Zoro, Jinbe etc... are there to get Luffy to the boss, not to fight the boss themselves.
So far, it seems that Zoro will handle Queen on the floor, Sanji will handle King in the sky/at the top, and Jinbe Jack on the rooftop. But after them, there is the problem of Big Mom.
Marco obviously can't handle Big Mom for the duration of the war. And Oda has already hinted at Straw Hats fighting Big Mom.
The Straw Hats will play the ultimate support role this arc. Just like their captain will take down a Yonko. They will gather all their strength to hold back another Yonko from interfering.
But remember. Commanders don't beat Admirals. They just hold them back for their captain.
Wano will also see Kid added to form the "Terrible Trio" formed since Sabaody. If you think Oda formed this trio for no fucking reason, you clearly have not been paying attention
So no, there is no room for a 4th actor here against Kaido. I think Zoro's role was hinted at in Dressrosa. Just like he fought an Admiral swordsman in DR, he will fight a Yonko swordsman in Wano.
But that won't be his "main" fight. His main fight is either Queen or King (that's not the end of it). Oda is recreating the "run to the top" scene here like he did in DR. Luffy/Law march to the top to fight boss while Zoro clears the obstacles (Pica). Here it will be a Calamity instead of a Seat, but afterwards Zoro helped with the birdcage. It wasn't JUST beating Pica.
Remember, the point of the commanders is to clear obstacles for the boss. Look at Jozu and Whitebeard.
Look at what Luffy says
Oda is emphasizing over and over and over and over, that Sanji, Zoro, Jinbe etc... are there to get Luffy to the boss, not to fight the boss themselves.
So far, it seems that Zoro will handle Queen on the floor, Sanji will handle King in the sky/at the top, and Jinbe Jack on the rooftop. But after them, there is the problem of Big Mom.
Marco obviously can't handle Big Mom for the duration of the war. And Oda has already hinted at Straw Hats fighting Big Mom.
The Straw Hats will play the ultimate support role this arc. Just like their captain will take down a Yonko. They will gather all their strength to hold back another Yonko from interfering.
But remember. Commanders don't beat Admirals. They just hold them back for their captain.