In the fanfiction, they could team up. Jack has all his ghost - hunting gadgets and Danny has his ghost powers. They could use their combined skills to fight a common enemy, perhaps a more powerful ghost that neither could handle alone. It could be a start of a new alliance between them.
A great plot point would be if they have to work together to reverse some sort of ghost - related disaster that Jack's inventions accidentally caused. Danny's powers and Jack's knowledge of technology could be the key to fixing it. And along the way, they grow closer as they overcome obstacles.
Blade Fangs was a Japanese manga created by Itagaki Keisuke. There were four works in total, namely Grappler Blade Fangs, Fanma Blade Fangs, Blade Fangs Path, and Blade Fangs Path 2. The theme of this manga was hand-to-hand combat, and it told the story of the young Blade Fang fighting with strong enemies in various underground arena competitions. The characters in the Blade Fangs series had distinct personalities, compact storylines, and unique styles. This series of comics was well-known in China and was welcomed and loved. The animated version of Blade Fangs also had two seasons and could be watched online. As for the viewing order of Blade Fangs, they could be viewed in the order of Blade Fangs 1, Blade Fangs 2, Fanma Blade Fangs, Blade Fangs Path, and Blade Fangs Path 2.