Some effects allow movement "as if the top and bottom edges of the realm were connected" e.g. .
To resolve these effects, imagine a duplicate copy of the realm above the top row, and below the bottom row. That is, those squares are considered adjacent for movement. Importantly, the squares are not actually connected for other effects, so something like on the top row wouldn't hit the bottom row, since Poison Nova isn't movement.
Moving "as if connected" does cross borders normally, and uses normal cardinal directions.
Oversized units that move as if connected and then find themselves spanning the realm will immediately end up on one side or the other. See "Oversized Units" for more details.
Forced movement effects do not cause units to take their own steps, and so they cannot cause a unit with such an ability to cross an edge of the realm. The only exception is if the edges of the realm are truly connected by some other effect (e.g. ).