The phrase "a crusader of" is correct and usable in written English.
It can be used to describe someone who passionately advocates for a cause or movement.
Example: "She is a crusader of environmental protection, tirelessly working to raise awareness about climate change."
Alternatives: "an advocate for" or "a champion of".
Eliot Spitzer was viewed as a crusader of uncompromising principle.
Civil-rights groups, many Laborites, and smaller liberal parties expected a different man, a crusader of another kind.
In doing so, he has acted as a crusader of sorts, challenging cable news norms -- and sometimes sticking out from the rest of MSNBC's daily schedule.
Here in the U.S., a large number of tributes to him have framed him as a crusader of human rights who died for good but the fact is -- and most Pakistanis will tell you, if they are not in the habit of pandering to Western imagery, that what really killed Salman Taseer was anything but an isolated -- though brave -- act of heroism.
Lindberg's piece was conducted by Rattle's CBSO replacement, Sakari Oramo, a crusader on behalf of the music of his native Finland, including Lindberg's.
Arianna Huffington, Editor-in-Chief of the Huffington Post, our AOL sister site, has been a crusader on the importance of sleep to your health.
Collins herself is something of a crusader for the art of engraving, and her fervor has produced a lively book called "The Complete Engraver: Monograms, Crests, Ciphers, Seals, and the Etiquette of Social Stationery" (Princeton Architectural Press).
Throughout his life he was a crusader for the rights of individuals with developmental and learning disabilities.
Today, Zeran imagines himself as something of a crusader for Section 230 reform.
The allegation runs counter to Gillibrand's reputation as a crusader for the rights of sexual assault and harassment survivors.
Knowles adopted the persona of a crusader, defender of movie consumers.
