Henry Arbinger was the alias adopted onEarth byMaestro'sHarbinger. A being created byMaestro, he referred to them as his "daddy". He resembled an unremarkable-lookinghuman child, and tookpianolessons withTimothy Drake, the composer who had rediscoveredthe Lost Chord capable of summoning Maestro into the universe, until Maestro decided to reveal themself. After they did so, Harbinger seemed to pop out of existence, leaving only a pile of clothes.

However, the child later reappeared, looking rather vexed, after Maestro was banished, looking on as theFifteenth Doctor andRuby Sunday sang and danced to "There's Always a Twist at the End". (TV:The Devil's Chord^[+]Loading...["The Devil's Chord (TV story)"])