[unofficial]He's part of a fiendpunk movement among younger drow to mark themselves with the symbols of demon lords they don't worship, as a way to thumb their eyes at their opponents and prove they fear nothing."[/unofficial]
[unofficial]He is part of a minor house with a different demonic patron cult that was acquired by Zeizerer as part of a.... hostile takeover.[/unofficial]
[unofficial]He made a high-stakes power play to become a major manager within Zeizerer... and lost. He was marked with that demonic sigil to ensure he'd never rise any higher. Which is why he's a contact between the House and the Starfinder Society.[/unofficial]
Many thanks Mr Stephens, any one of those would work, and that's why we'll miss you so much!! Good luck for the future by the way.