When a necromancer dies as a worshipper of Mannimarco, what happens to his soul? Does it join with the Revenant, or does it go to the dreamsleeve?

And what is the relationship between the God of Worms and the Ideal Masters now, post-apotheosis?

A.) It is assumed they go onto the dreamsleeve. Manimarco's goal is, depending on the viewer, to either eclipse Arkay onc a week or to be a hole in the equation that is Arkay once a week,

B.) They would most likely be competitors, but honestly we don't know.

They would go to the Necromancer's moon, to await summons from other Necromancers and/or Mannimarco's bidding.

Mannimarco and the Ideal Masters likely share some business relationship, or a rivalry. Could be either or, or even both depending on the scenario.