The Lead

Rughsbourgh was very crafty and definitely knew what he was doing from the first day he sent them to the heart of that disaster.

Northern didn't want to believe he didn't actually expect them to return.

So was becoming a Luminary his fail-safe?

No. It couldn't be; it was too magnanimous to be a fail-safe. It had to have been Rughsbourgh's goal all along.

Becoming a Luminary.

That would explain to a degree why he had found a way to artificially force open rifts. If he wanted to have access to stronger monsters, he'd have definitely done that.

However, wasn't it dangerous? Why the need for so much power?

Northern's mind automatically generated the answer following the question it posed.

'The more you get, the more you want?'

Until one got to the pinnacle, as far as they had resolve, they wouldn't stop striving to become stronger.