Monsters with keyword fly query

[BLACK BLΠFLY]

Can Monsters with keyword fly enter ruins or buildings ?

[Cheex]

The Breachable trait doesn't matter, as the FLY keyword lets you ignore the vertical distance when moving over terrain. The Scaleable trait also doesn't matter as it provides a specific exception for all FLYING models.

 

The only thing that could stop a FLYING monster is the physical space to put the model.

[Xenith]

As per above. Remember that BREACHABLE is only for infantry, so if you're on one side of a wall and want to fly up and over a ruin to charge a unit on the other side, you also need to fly around and back any other levels in the ruin to get at them. (I think).

[BLACK BLΠFLY]

How’d that work with a completely enclosed ruin?

[Xenith]

If you can't physically put the minis inside, they can't go inside. If they have enough move for the entire unit to go straight through, then they can start on one side and end up on the other. Ruins are still scalable, however, so models can also go up and over if the unit would have to finish it's move with some models in the ruin. Or agree with your opponent that they're 'in' the ruin, but this needs some abstraction.