She wanted to sing. Alina was so beautiful. So incredibly, painfully beautiful. Kazelia wanted to sing her praises forever and exalt her in the halls of the greatest princesses in all the universe. But she knew it was a lie. Mother knew, she had been railing against everything the Caduceus made since they first got here because none of it was true. The Caduceus was an overlay that fell over people, a cheat from the devils that simply altered reality. But Mother knew that cheating wasn't truth. Magic might [i]be[/i] someone's truth (it was probably a part of how Kazelia's was expressed, likely Azora's as well) but changing yourself with magic never [i]changed[/i] your truth. 

Also, all that philosophical reflection aside, Kazelia wanted her friend back. The happy ending here wasn't replacing one Caduceus wielder with another, distant and open only to worship and painting reality as her canvas. A happy ending was having her friend back and saving the world from Oberon and mad devil things alike! 

That's why Kazelia's answer to this wasn't to raise her spear or gesture for Kyouko to use her ninja tools (don't think she wasn't paying attention). Instead it was to drop that spear and let the rainwater run over it without any steam hissing up from its fire. It was to stand beneath Alina and raise her arms in a gesture of begging and just say one thing. "I stopped singing because I don't want to lose my friend, Alina. Please, come back to us. To me."