@okestra
you, me and a lot of other people have similar theories about Mr bones being the dimension knight.
That said, personally, I believe it's just him, helping himself grow.
The events have some pretty big similarities if you think about it.
both times a necromancer was involved. ( Rae Rubia and Gilles de Rai )
both times there were two factions fighting over something ( the fake emperor and magical McGuffin )
Both times he was left alone with a ton of corpses.
And both times something bad happened right afterwards that made him strive harder to grow stronger still. ( Leandro hunting him down, and getting stuck in a time bubble so he fails to save Rubia )
I don't think he is being controlled, but that the system is limiting the amount of interference one of his lives can have on his other lives.
We have seen it do some shady stuff in the last 50 chapters or so...
Also from the sound of
Edgar Allen Poe the Raven wizard guy ( forgot his name ) he doesn't go back in time as much as he jumps between dimensions when he dies
( this means that theoretically, his other copies of himself should be able to help him out. )