In another timeline, it was Marcus who became the Dark One.
I think this was sparked by my earlier musing that there had to be at least one timeline where Durandal took Hathor with him to Lh’owon.
For AI!Marcus (now going by ‘Quintus’?), I wanted him to look somewhat cyberpunk-y to contrast with normal Hathor’s more fantastical getup. While I’m not yet sure exactly how a reverse-Eternal would play out, I feel like Marcus would be a bit more subtle about pursuing his own goals early on, before the stress begins having deleterious effects on his sanity.