Portraits revealed through your current reading position.
The small child Mordecai holds in his arms as the city transfers without them.
In Carl's last look around Larracos before Zerzura fired, Mordecai was there holding little Ruby in his arms. Mordecai did not transfer with the spell.
'It's best, little one,' he told her — the two of them staying behind as the city and its people were lifted away to The Twelfth Floor.
A small child, small enough to be carried in Mordecai's arms.
A child left behind with Mordecai when the city transfers.
Also appears in books you've already read — spoiler-safe to their endings: