The phrase "a shadowy force" is correct and usable in written English.
It can be used to describe an ambiguous or mysterious power or influence, often with a negative connotation.
Example: "The town was rumored to be under the control of a shadowy force that manipulated events from behind the scenes."
Alternatives: "an elusive power" or "a mysterious influence".
Mr. Zivkovic promised that the police would serve citizens, work openly "and not be a shadowy force".
Iraqi and British officials have suggested that Mr. Sadr's militia is tied to hundreds of policemen in Basra who form a shadowy force called the Jameat, a group involved in killings and torture.
For there is a shadowy force lurking behind the scenes, determined to demand the submission of all who refuse to acquiesce and conform.
A rapper with prodigious talent, armed with perhaps more potential than even Illmatic-era Nas, Electronica has largely remained a shadowy force.
A shadowy force attacks the lodge, Alan goes to Hartman's room and he sees the kidnapper in a picture of clinic staff with Hartman, then he finds the manuscript and learns that Hartman is a liar and all the events are real.
The archaeological site of Çatalhöyük may lie 130km to the southwest, but at 3,253m high and with only rippling plateau in between, the stratovolcano (its conical shape built up by strata of pumice, ash and lava) remains a domineering and shadowy force on the Neolithic town's horizon.
The Sunday People alleged a female member of the shadowy Force Reaction Unit (FRU), the army intelligence outfit that ran 100 agents, suggested that loyalists kill Notorantonio.
As would emerge later, among those killed were up to a hundred Russian citizens who were fighting in Syria as private military contractors, a shadowy mercenary force whose presence in Syria is not officially recognized by the Kremlin.
Because, the assumption goes, rape is a shadowy, inevitable force out there waiting for silly women who walk into its path, not the deliberate act of an individual criminal.
The conversation on Nov. 19 was a flashpoint in a tumultuous year in which Zuckerberg came to recognize the magnitude of a new threat — a coordinated assault on a U.S. election by a shadowy foreign force that exploited the social network he created.
But what it really resembled was a script from a horror movie about teenage girls and demonic possession: a shadowy, evil force had inscribed itself into their minds – via an electronic screen – and turned them into sex-mad, husband-chasing, ideological fanatics, whose parents could no longer recognise them.
