When child-Idia sees “Subject ROS-3367A,” the creature that he accidentally releases when he shuts down STYX’s security, he doesn’t call it a phantom.
He calls it a monster.
When asked about his family Grim responds, “I remember wakin’ up hungry and alone. It was real cold. I was waitin’ out there for someone to come get me for ages. What happened after that again? It’s all so foggy…”
And we have heard about creatures who are hungry, cold and alone before: Tartarus’ phantoms.
Other curiosities are:
1. STYX is unable to fully analyze Grim because of a curse/blessing he is under
2. STYX is fairly certain he is a direbeast combined with another, unknown animal
3. There are creatures known to disguise themselves as direbeasts to escape detection: phantoms.
While STYX did not identify Grim as a phantom in their analysis they have been wrong before, with Idia describing Grim as “as lackluster with magic as he looks,” only for Grim to then magically explode a magic-resistant door.
A STYX technician explains, “His test results for magic performance were all subpar compared to an average mage…we had no indications he had the kind of power it would take to destroy that door. None at all.”
Idia also reports, “Grim’s numbers go haywire every time I try to get a precise blot accumulation reading. One moment they spike into the red zone, like a subject that’s gone full Phantom.”
And there is at least one theory that ties in to how we technically do not know how it is that original-Ortho died: he was killed by an escapee from Tartarus, but Idia says that, when he woke up, “Ortho was gone.”
And at least one of the phantoms we see wake up Tartarus demands to be fed flesh. Was original-Ortho eaten by a phantom? And was that phantom the infamously hungry Grim?
Tying in the theory that the “ROS” from “ROS-3367A” comes from “Queendom of Roses” and Grim was based on Dinah from Alice in Wonderland, and the game may be hinting that Grim killed Ortho.
Twisted Wonderland Reference Note 