Bricky Steve is 16yo's friend's (aka "the other 16yo") player character, a mage who accidentally created a "perfect brick" (known as "The Ubrick" as they portmanteaud uber brick) and is now on a mission to try and recreate it, and thus developed an obsession with bricks. It's only us players that seem to call him Bricky Steve, he's just "Steve" to the other characters.
He lives and works on Captain Gundry's airship and seeems to be maintenance personnel more than anything (he's spec'd mental/social/physical) as in the last session he stayed on board with Gundry and Yue while everyone else (including 16yo's character) raided another ship, and did a lot of magic repairs to the balloon when their ship came under Umbral attack.
He's also an apprentice to some obscenely high level mage