Well, he's "preparing to start using" Okui's glaive. The one's he's got now is a different one. Here's what Ouki's looks like:
What's nuts tho is what I realized while lookin it up:
There he is with that exact glaive in chapter 1. SPOILER ALERT!??!
Since the shield isn't here, I wonder if that wasn't planned out as well as the glaive?