Tian Ge Wuxiang Sword Qi was a divine technique developed for "ambushes." Although the fluctuations of sword qi were difficult to conceal, its visual "invisibility" lent it a touch of bewildering deception. It could employ principles ranging from far infrared to far ultraviolet light, using invisible Sword Light to cut down opponents.
However, once the Immortal Alliance discovered that many species in this world possessed visible-light ranges entirely different from those of the human race, it lowered its evaluation of this spell considerably. The Third Division of the Dark Department also strongly discouraged its use internally.
But at other times, this spell could still prove useful.
For instance, disinfection.
Starship Magical Items, as well as any items from other biospheres aboard starships, had to undergo bombardment by this Sword Qi before entering another biosphere—including, but not limited to, the biosphere of Divine Land Houtu. If a starship wished to enter the atmosphere, it had to remain exposed to Wuxiang Sword Qi or similar spells for as long as five shichen.
And now, Song Shufu clearly intended to use this spell to do something.
An invisible, formless strand of Sword Qi slashed out, passing through that tube of solution.
Then the job was done.
"The finest ultraviolet instrument I can buy still can't distinguish frequency bands as minutely as I can by controlling it myself, so I completed this step personally—and it was faster, too," Song Shufu said. "This is its most terrifying trait—even ultraviolet irradiation has a hard time killing it."
Chen Feng froze.
Not from shock, but because...
This looked far too familiar.
Yellow Crystal plague poison likewise possessed extraordinarily strong resistance to ultraviolet light...
The principle behind ultraviolet inactivation was the excitation of free radicals—that was, using light to transfer energy, causing uneven cleavage of covalent bonds within