Continuing the Sun Demon and Sun Titan cycle, we come to Grave Titan. Who is a token maker; and thus, um, live in green in the old days and white nowadays? Wtf?

so the obvious shift-back would be a grown up version of Cadaver Imp

How about killing tokens? Black gets to outright Murder stuff, so that should be ok. Murder on ETB is too good, but murdering a token? That's a very minor effect. Possibly too minor. Let's expand it to nuke artifact copies too - black doesn't usually gfet to do that, so it's a bit of a stretch; but they're kinda rare so it's probably ok to have some collateral to continue my "Try and find a sneaky sue for this" theme.

Still, this one's usually gonna be a junk rare.

This is an interesting colourshift, actually, because so far the effect has normally been white: Dogged Hunter. I don't see why you'd make this claim to be a token itself though. That makes this like a really bad Knight of the Mists.