Marz's 2000s work includes a number of Top Cow Productions comic books, including Witchblade, which he wrote from issue #80 (Nov. 2004) to issue #150, plus a number of specials and crossover stories featuring the character, such as Witchblade/The Punisher in 2007 and Witchblade/Devi in 2008. His other Top Cow work includes Cyberforce #1–6 in 2006 and Cyberforce/X-Men in 2007.
For DC Comics, he has written Ion,[6] a 12-part comic book miniseries that followed the Kyle Rayner character after the One Year Later event, and Tales of the Sinestro Corps Presents: Parallax and Tales of the Sinestro Corps Presents: Ion, two one-shot tie-ins to the Green Lantern crossover, The Sinestro Corps War.
In 2008 Marz wrote Broken Trinity, which featured the characters Witchblade, The Darkness, and Angelus, as well as the tie-in series, Broken Trinity: Witchblade, Broken Trinity: Angelus (2008), and Broken Trinity: Aftermath (2009).[9][10] He signed an exclusive contract with Top Cow, which saw him write three comics a month: two for Marc Silvestri's Top Cow universe, and a creator-owned project.[11]
In 2011, Marz was the writer on Voodoo, which was part of DC Comics' company-wide title relaunch, The New 52.[12]
In 1999, Gail Simone introduced the term Women in Refrigerators to highlight a troubling trend in comic narratives: the use of female characters' suffering—through death, injury, or assault—as mere plot devices to advance male protagonists' stories. This concept was sparked by an event in a 1994 Green Lantern issue written by Ron Marz, where Kyle Rayner discovers his girlfriend Alexandra DeWitt's fate at the hands of the villain Major Force, who had murdered her and left her body in a refrigerator. Simone's critique aimed to shed light on the broader issue of gender bias and the disposability of female characters within the genre.[14]
In response, Marz stated: "To me the real difference is less male-female than main character-supporting character. In most cases, main characters, 'title' characters who support their own books, are male. ... the supporting characters are the ones who suffer the more permanent and shattering tragedies. And a lot of supporting characters are female."[15] He also further explained:[15]
I created her [Alexandra DeWitt] with the intention of having her be murdered at the hands of Major Force. I took a lot of care in building her as a character, because I wanted her to be liked and her death to mean something to the readers. I wanted readers to be horrified at the crime, and to empathize with Kyle's loss. Her death was meant to bring brutal realization to Kyle that being GL [Green Lantern] wasn't fun and games. It was also meant to sever his links with his old life, paving the way for his move to New York. And ultimately I wanted her death to be memorable and illustrate just how truly heinous Major Force was. Thus the fridge.
^Manning, Matthew K.; Dolan, Hannah, ed. (2010). "1990s". DC Comics Year By Year A Visual Chronicle. London, United Kingdom: Dorling Kindersley. p. 272. ISBN978-0-7566-6742-9. Written by Peter David and Ron Marz with art by Dan Jurgens and Claudio Castellini, this four-issue miniseries event consisted of five major battles voted on in advance by reader ballots distributed to comic stores.{{cite book}}: |first2= has generic name (help)CS1 maint: multiple names: authors list (link)
^Manning, Matthew K.; Gilbert, Laura, ed. (2008). "1990s". Marvel Chronicle A Year by Year History. London, United Kingdom: Dorling Kindersley. p. 265. ISBN978-0756641238. Writer Ron Marz and penciller Joe Phillips created Genis-Vell...Originally going under the code name Legacy...He was later known as Captain Marvel.{{cite book}}: |first2= has generic name (help)CS1 maint: multiple names: authors list (link)
^Manning "1990s" in Gilbert, p. 281: "In this four-issue miniseries, writer Ron Marz and artists Jackson Guice and Josef Rubinstein featured interesting pairings, such as Venom battling Superman."
^Manning "1990s" in Dolan, p. 264: "In 'Emerald Twilight', a three-issue saga penned by new writer Ron Marz and drawn by artists Bill Willingham, Fred Haynes, and Darryl Banks, longtime Green Lantern Hal Jordan set out to right the wrongs done to him."
^Cowsill, Alan "2000s" in Dolan, p. 325: "Ron Marz and artist Greg Tocchini reestablished Kyle Rayner as Ion."