Lin Mo ignored Kael's question about what a bank was and asked in bewilderment:
"Why does a permanent one cost so much more?"
"Because of the world barrier."
A hint of sanctity appeared on Kael's face, as though he were explaining a fundamental truth of the world.
"Between worlds, there are sturdy spatial barriers with powerful self-repair capabilities."
"A temporary portal is like a small cut in the skin. It bleeds, but the barrier's own restorative power soon heals it."
"We only need to keep the passage open before it heals."
He gestured as he spoke.
"But a permanent portal is different."
"It's the equivalent of implanting a 'brace' that will never be rejected into that 'wound,' forcibly fixing the spatial passage in place and making it an eternal spatial opening in the world barrier."
"That requires resisting the restorative laws of an entire plane. Naturally, the precious materials consumed and the effort required are worlds apart."
As Lin Mo listened, he understood.
What Kael called "the world barrier repairing itself" sounded to him like "the natural tendency of spatial curvature to flatten out."
And the so-called "implanting a brace" meant establishing a singularity capable of continuously putting out tremendous energy to forcibly maintain a stable spacetime wormhole.
Put that way, five million gold coins actually seemed quite reasonable.
"What if we need to expand it?" Lin Mo continued asking.
"For instance, we have some fairly large equipment to transport."
"Expand it?" Kael thought for a moment.
"For an Astral Portal, every additional meter of circumference costs another ten thousand gold coins in materials."
He seemed to notice that Lin Mo thought it was expensive and volunteered an explanation:
"That's already quite reasonable, Holy Son."
"For an ordinary portal, it would only cost a thousand gold coins per meter."
"But