Ah no, sorry. I get what you mean now. The scene where that happens should be in the middle of the battle where only Siena and Ning Jun fights against Piero. If you haven't reached this scene yet, then that means you have to continue battling until Erika and Kain are defeated (yes, you cannot win this battle!) Once you lose, Siena and Ning Jun will come to play. So sorry for the confusion and (unnecessary) spoilers!
no problem! also, i've got another question about a possible bug (or perhaps just me not getting it lol).
SPOILERS
i'm currently stuck on onyx's party in the basement of piero's castle attempting to locate the node. i've been trying for a while and have gone on what i think is every route thats walkable. could i have a hint on where the node is? if only i could swim lol. thanks!
Hi again! *SPOILER ALERT*
I'm assuming that you're having a problem finding where to go right after Siena and co. split up in the sewers? If that's so, just head right to where Onyx is currently (image below). It's not very apparent, but it actually leads you to another map with waterfalls, and if you keep heading forward, you should find a lever...
I hope that gives you a hint? Do tell me if I misunderstood the question, and thank you for playing!