The active lava flows of the Nexus make for an ideal cover. There's no reason to believe anyone could travel through them safely.

They aren't big enough for vehicles, and they're completely inhospitable to anyone without the defense of the jewel.

And why would we bring the jewel in through them, huh?

Exactly.

Even if they knew about the existence of the tunnels, which we have every reason to believe they don't, the tunnels appear to be only ways OUT of the Nexus, not in.

They can't seal them off, due to the fact the Nexus' active flows would just open them back up again. They have no reason to believe anything can come OUT of them, since the Nexus' flows leave through them.

The perfect blend of craziness, for us to come in through them.

We did something similar at the Nature nexus, believe it or not. The great tree's roots actually change their paths every few years.

As such, there's a number of abandoned, and mostly sealed off, tunnels. I'm guessing every nexus has some kind of similar mechanism, honestly. I see no reason the Air and Water nexuses wouldn't have them, as well.

Their existence only is known to the monks and clever tribal leaders, like myself.

Even if they know about the tunnels somehow, the flows all head downward. There's no visible way to come back in.

Which we're doin', how, exactly?

The monks have told us that a fire aura protects from the magma flows, believe it or not. They can just walk right on top of it safely.

Which makes sense. The flows are liquid rock, and the auras protect from the extreme heat, so you can just walk up or down the flows themselves.

And that's why my teaching you the aura extension magick is so important. With the jewel's protections, all of us should be able to walk right up the active flows with no problem at all.

And with the Fire crystal's protections, I can use my magick to create a few shennanigans. They definitely won't be expecting to deal with a strong Nature mage at the Fire nexus.

My nature magick can stop and subdue any soldiers we would encounter, and give us direct access to the command location of the Air forces.

I'm not entirely sure WHY there's a back door into each of the nexuses, only available to those attuned to it, but it's a useful secret feature to them. And one that benefits us now!

I'm actually curious if your interactions with the Elemental Temple's machine brought any insight into why that might be. SHINE, wasn't it called?