@FrettzoIt's not actually another plane, but it's easier to describe it that way.
It's the innate energy within each
thing, and the relationships between said
things. Every material object --
thing -- has/is magic (occult) energy. The submaterium is the sort-of realm within
things where this energy (and the relationships; cables) is expressed. Hence the name -- submaterium.
@CycloneYeah, you unlock the energy in the material world in order to perform magic. Said magic then has to be weird and evil-ish (witchy rather than magey).
Trinkets (what I'm calling occult objects, like rings) will be a thing -- and they will be generically magic. Like -- a crown that bends the will of those around you, or a belt buckle that prevents you from getting more than slightly tipsy. A monocle that allowed you to see the shifters
would actually be possible -- by giving you extremely good perception so you notice what isn't actually air, for example. This would be very high level from the sounds of it, however; submaterial scuba-diving is easier.
A ritual, by the way, is any process in which the magic within
things is released. Smashing gem stones, pouring blood into a labyrinth-well, hacking down a special tree.