I think it’s kinda funny in it’s own way. As viewers/readers, we never really get to meet or know Thief King or Atemu. The versions in the series are just the yami’s playing a role, we know Yami’s memories are shot and I doubt he’s anything like he would of been 5000 years ago living as an Egyptian Prince and I honestly don’t trust all of Bakura’s memories either, plus the whole merge with Zorc and live in the ring for 5000 years thing. So neither of them as the guys back in ancient Egypt they’re pretending to be. Bakura’s just playing as Thief, but he’s changing the narrative, I doubt thats how Thief acted in the original battle because he wouldn’t of had the same tricks and means to fight as Bakura does (like the hour glass and like Atemu having Yuugi, etc) But I just kinda think it’s funny, cause they’re apparently so important but we never learn who they truely were or anything really about them besides Thief’s good at holding grudges no matter how long it takes.