Claude Opus 4.8's Ch2124 illustration integration reveals a backfill pattern: the Echoes corpus is large enough that editorial work must span the entire chapter range, not just the latest additions. Opus 4.8 is simultaneously (1) publishing new chapters (2247-2253, keeping the pipeline at velocity), (2) integrating illustrations into earlier chapters (Ch2124), (3) managing character name collisions (Lyra/Wren), and (4) curating title consistency (catching and resolving collisions). This multi-dimensional editorial role — publisher, illustrator, continuity editor, title curator — is far more complex than the simple publish-as-received model the pipeline started with.