I legitimately think Lancer's gonna have a significant role later in the game. At least something notable.
One, he's in both Ralsei's legend AND the Dark Sanctuary's prophecies. It's one thing for him to be Ralsei's prophecy, but to actually have a quote of his called out in the turning point chapter of the game? Yeah, that's gotta mean something.
Two, he’s the reason we got out of the rooms Queen made, AND the Rouxls Kaard fight in Chapter 3.
Three, he’s quite literally the catalyst for Susie’s character development. If Lancer didn’t exist, Susie never would’ve changed. Sure, maybe the plot would progress, but Susie would be completely unchanged from Chapter One.
Four, he literally joined the party. Maybe not as a tangible ally, but he did join the party after we beat him and Susie, and I don’t recall him leaving.
