Chapter 175: The Heavenly Tribulation of Worldly Calamities, Life Span Tribulation

Outside the Ninth Grotto Heaven, a thin light barrier trembled slightly.

"Has it begun?"

Gu Wen and Jun Yan pressed their ears against the light barrier, faintly hearing collision sounds.

This barrier, impervious to all methods, did not block vibrations; most barriers against the outside world worked likewise, especially fixed arrays.

Because there was no need—vibrations, sounds, light, and so on did not provide outsiders with any useful information. Most cultivators probed with Divine Thought, and guarding against such probes was of the utmost importance.

An additional function in a Daoist Skill meant doubling the effort and concentration; the same was true for arrays. The more complex the functions, the more prone to error.

The truly top-notch spells usually had only one function, either offensive or defensive. Those that were meant for both were generally crude spells from the marketplace of the cultivation world.