@Cuccoruler Well, it seems like Calamity could annihilate most of the current player cast. So putting him opposed to the players would most likely end in a crushing defeat for the good guys. If he really can destroy skyscrapers, then we're just not ready to face off against him. Especially as at least 2 characters will be on Calamity's side, not counting Calamity's npc allies.
I would recommend having Zera move in with an immense army, and give him a good shot at world domination. Set Cataclysm up as a third party in the battle. He doesn't like the heroes, but he dislikes Zera more. Zera should have enough mooks in his army to give the heroes a chance to kick ass, and Cataclysm can be distracted by the Kraken attacking, or something. If the players stay on Cataclysm's good side, he helps them beat Zera. If not, he attacks Zera independently, and the Cataclysm characters and heroes could have a clash aboard Zera's mothership, or Atlantis, or whatever.
Most importantly, don't set the result in stone. If the players defeat Zera, Cataclysm becomes the next foe, and they're forced to use the experience and weapons they gained from their previous adventure against the immensely powerful Cataclysm. If Zera wins, the world is conquered by fish people, and Cataclysm might be a useful ally or even leader to the rebellion the heroes would be a part of. If Cataclysm wins and the players hate him, he conquers the Earth like a bad guy, and the players need to use guerilla tactics to recover artifacts or something to defeat him. If Cataclysm and the players work together for victory, the people from Cataclysm's homeworld might show up, and we might have to save Cataclysm while avoiding interdimensional war.
Alternatively, you could do it the other way around. Cataclysm is the Big Bad, and Zera is the Third Party. But Cataclysm just seems closer to the edge, like he could be both good or evil, depending on the circumstances. And Zera seems like he would have a large army, which gives everyone a chance to show off their powers and explosions against weak enemies.
I would recommend having Zera move in with an immense army, and give him a good shot at world domination. Set Cataclysm up as a third party in the battle. He doesn't like the heroes, but he dislikes Zera more. Zera should have enough mooks in his army to give the heroes a chance to kick ass, and Cataclysm can be distracted by the Kraken attacking, or something. If the players stay on Cataclysm's good side, he helps them beat Zera. If not, he attacks Zera independently, and the Cataclysm characters and heroes could have a clash aboard Zera's mothership, or Atlantis, or whatever.
Most importantly, don't set the result in stone. If the players defeat Zera, Cataclysm becomes the next foe, and they're forced to use the experience and weapons they gained from their previous adventure against the immensely powerful Cataclysm. If Zera wins, the world is conquered by fish people, and Cataclysm might be a useful ally or even leader to the rebellion the heroes would be a part of. If Cataclysm wins and the players hate him, he conquers the Earth like a bad guy, and the players need to use guerilla tactics to recover artifacts or something to defeat him. If Cataclysm and the players work together for victory, the people from Cataclysm's homeworld might show up, and we might have to save Cataclysm while avoiding interdimensional war.
Alternatively, you could do it the other way around. Cataclysm is the Big Bad, and Zera is the Third Party. But Cataclysm just seems closer to the edge, like he could be both good or evil, depending on the circumstances. And Zera seems like he would have a large army, which gives everyone a chance to show off their powers and explosions against weak enemies.
