Question: The co-developer of the "Fuzion" system published what game on their own?

Context paragraphs:
Fuzion: Fuzion is a generic role-playing game system created by the collaboration of R. Talsorian Games and Hero Games.  The rights to Fuzion are jointly held by Mike Pondsmith of R. Talsorian Games, along with Steve Peterson and Ray Greer of Hero Games.  "Fuzion" is a combination of the Interlock System, (used in games like "Mekton" and "Cyberpunk 2020"), and the HERO system (used in "Champions", "Justice, Inc.", "Star Hero", etc.).  "Fuzion" is an adaptable system which can be played in any genre and setting imaginable.

D20 System: The d20 System is a role-playing game system published in 2000 by Wizards of the Coast originally developed for the third edition of "Dungeons & Dragons".  The system is named after the 20-sided dice which are central to the core mechanics of many actions in the game.

Trewartha climate classification: The Trewartha climate classification is a climate classification system published by American geographer Glenn Thomas Trewartha in 1966, and updated in 1980.  It is a modified version of the 1899 Köppen system, created to answer some of the deficiencies of the Köppen system.  The Trewartha system attempts to redefine the middle latitudes to be closer to vegetation zoning and genetic climate systems.  It was considered a more true or "real world" reflection of the global climate.

D6 System: The D6 System is a role-playing game system published by West End Games (WEG) and licensees.  While the system is primarily intended for pen-and-paper role-playing games, variations of the system have also been used in live action role-playing games and miniature battle games.  The system is named after the 6-sided die, which is used in every roll required by the system.

Tychonic system: The Tychonic system (or Tychonian system) is a model of the Solar system published by Tycho Brahe in the late 16th century which combines what he saw as the mathematical benefits of the Copernican system with the philosophical and "physical" benefits of the Ptolemaic system.  The model may have been inspired by Valentin Naboth and Paul Wittich, a Silesian mathematician and astronomer.  A similar yet mathematically more efficient geoheliocentric model was also proposed a century earlier by Nilakantha Somayaji of the Kerala school of astronomy and mathematics.

Danger International: Danger International is a role-playing game published by Hero Games in 1985.

The Ignition Factor: The Ignition Factor, known in Japan as Fire Fighting (ファイヤー・ファイティング ) , is a video game for the Super Nintendo Entertainment System published by Jaleco.  The game features firefighters in realistic situations saving civilians in burning buildings, mining incidents, and industrial accidents.  It was released on the Wii Virtual Console in Japan on March 1, 2011, in the PAL region on April 29, 2011, and in North America on August 25, 2011.

Hamamelidales: Hamamelidales is an order of flowering plants formerly accepted in a number of systems of plant taxonomy, including the Cronquist system published in 1968 and 1988.  The order is not currently accepted in the Angiosperm Phylogeny Group III system of plant taxonomy, the most widely accepted system as molecular systematic studies have suggested that these families are not closely related to each other.  The APG II system (2003) assigns them to several different orders: Hamamelidaceae and Cercidiphyllaceae to Saxifragales, Eupteleaceae to Ranunculales, Platanaceae to Proteales, and Myrothamnaceae to Gunnerales.  Additional studies of the chloroplast genome have since confirmed that the families moved into the Saxigragales are closely related.

Hero Games: Hero Games ("DOJ, Inc dba Hero Games") is the publisher of the Hero System, a generic roleplaying rules set that can be used to simulate many different genres, and was the co-developer of the "Fuzion" system.

Phoenix Command: Phoenix Command was a role-playing game system published by Leading Edge Games, and copyrighted by Barry Nakazono and David McKenzie.  Various versions of the system featured in the games "Morning Star Missions", "Living Steel", and "Aliens Adventure Game".

Supporting paragraphs: Danger International Hero Games
Answer: Danger International