Warning: The following contains spoilers for Doron Dororon Chapter 5, "Cooperation," by Gen Oosuka, Camellia Nieh, and Phil Christie available in English at Viz and Manga Plus.
Doron Dororon revolves around monsters called Mononoke, and only those who can wield supernatural energy can deal with them. The main protagonist, Dora Sasaki, isn't one blessed in this department -- similar to Black Clover's Asta. Before learning the harsh truth, Dora already honed his physical abilities to an almost superhuman degree. Things changed when he met Kusanagi, a human-loving, shapeshifting Mononoke, giving him a chance to fight back. Chapter 5 showed a new form that gives further insight into Kusanagi's fighting style.
Dora and Kusanagi's pairing is a match made in heaven. The boy's immense physical prowess compensates for his lack of supernatural energy, and the monster's shapeshifting ability provides the perfect weapon for his Mononoke extermination deeds. In their first meeting, Kusanagi transformed into a heavy long blade that Dora swung single-handedly, resulting in their victory against a Mononoke they wouldn't be able to kill otherwise. They used the same tactic in their subsequent fights, giving the impression that Dora is treading the path towards becoming a swordsman.
In Chapter 5, Ginchiyo brought Dora and Kusanagi to her house, giving the two a glimpse of her background. They were discussing the unusual pair's motivation when a report about a Mononoke abducting some humans came in. The three responded and Ginchiyo acted as the main force. The female samurai quickly got a sight of the Mononoke still carrying humans on its shoulder and quickly cut it into two. However, she quickly realized that there wasn't any resistance and the fight wasn't over yet.
The Mononoke separated into 100 little Mononoke, revealing its true identity -- a 100-eyed Boy or a Hyakumekozou. Ginchiyo's quick response allowed her to cut a good amount of them, but there were too many for her to exterminate before they escaped. Dora, holding a fan-shaped Kusanagi, came into the rescue and fanned the monsters back so Ginchiyo could finish the task.
Dora's compatibility with Kusanagi's long blade form gives the impression that the protagonist will be following the way of the sword throughout the series. Their flashy debut fight and the fact that the manga is about samurai further reinforce that image. This is still a highly-likely scenario, but the developments in Chapter 5 suggest that Dora is a more flexible fighter.
Doron Dororon has done a good job expressing how observant Dora is, which is also how he figured out he can use Kusanagi as a weapon. Dora's observation is evidence of how good a fighter he is, be it unarmed, using a sword, or a fan. And him using Kusanagi as a giant fan indicates that he has no qualms about using any weapon as long as it can get the job done. That doesn't necessarily mean he'll become a formless fighter, but it may mean fans will be seeing Kusanagi in different forms as long as the situation calls for it.
There is no problem with being a powerful sword and killing Mononoke. However, this may seem like an unnecessary limitation to the potential uses of Kusanagi's shapeshifting skill. This development indicates that Dora isn't limiting himself to using a long blade. As such, fans will be seeing more of Kusanagi in different shapes and sizes as well as Dora's problem-solving in future chapters of Doron Dororon.
