Another possible main character could be Kakashi. As Naruto's teacher, he would play an important role in guiding Naruto with this new ability. He could be helping Naruto to control and develop his iron skin further, and also be involved in strategies that make use of this unique power in their missions.
Sasuke could also be a main character. In the Naruto universe, Sasuke is Naruto's rival and friend. In the fanfiction, he might be involved in battles against Naruto to test the limits of his iron skin, or they could be teaming up and Sasuke could be using Naruto's iron skin as a form of protection in dangerous situations.
Well, one interesting idea could be the unique ways Naruto's iron skin ability is used in battles. Maybe he can withstand extremely powerful attacks and use that to his advantage by getting close to the enemy without fear of getting hurt.
Since I haven't read this particular fanfiction, it's hard to say for sure. But in RWBY, it could be Ruby, Weiss, Blake, and Yang. Maybe the 'words on skin' concept is related to one of their stories, like Ruby finding some strange words on her scythe which is an extension of herself, and it leads to a new adventure for her and her team.
Naruto is obviously a common character. He often visits the Land of Iron or gets involved in events related to it. Sasuke might also be there, as his journey often intersects with Naruto's. Then there are the samurai from the Land of Iron, like Mifune. He is a respected figure and could play a major role in fanfictions set in the Land of Iron.
The characters included the male protagonist, Jiang Chen, who was decisive in killing and had a sister complex. "Opening Level Maximum Iron Shirt" Author: Panda Rollball. It was a fantasy/otherworldly novel with transmigration, system style, maturity, decisive killing, hot-blooded, extreme style, and opening style elements. [User recommendation: Jiang Chen accidentally activated the system to change the time of all things when he transmigrated to a world where demons ran rampant.] Changing the cultivation time of the Iron Skin Technique, raising the cultivation technique to the maximum level and advancing to the Golden Armor Iron Skin Technique! Changing the growth time of spiritual herbs, turning ordinary spiritual herbs into ten-thousand-year-old spiritual herbs, greatly increasing one's strength after consumption! Modifies the forging time of the ancient weapon, restoring the rusty iron sword to its peak condition. Obtained a divine sword! Suddenly, one day, you picked up a set of bones of the Great Empress from 10,000 years ago. …… Changing the lifespan of the empress and reconstructing her body from her ten thousand years old bones! Congratulations, you have obtained a Qingcheng Empress! I hope you will like this book.
Perhaps there is a new vampire character whose origin story is connected to the etching on their skin. This character could be the central focus, with their interactions with the known Twilight characters driving the story. They might be in conflict with some of the traditional vampire clans because of their unique marking.
I don't know for sure since I haven't read this specific fanfic, but it could be characters like Gaara. Given his connection to sand, he would be a likely candidate if the fanfic focuses on iron sand.
Often, new original characters created specifically for the fanfiction and possessing the iron bloodline can be popular. They bring fresh perspectives and abilities to the Naruto universe. Also, some minor characters from the original Naruto series might gain more popularity when given the iron bloodline in fanfiction, as it gives them a chance to shine in new ways.
There was not much difference in efficacy and medicinal value between the purple-skinned and the candied ones. Both of them had the effects of nourishing yin and nourishing the lungs, clearing the liver and improving eyesight, and were suitable for modern health care. However, the effective components, content, and quality of the medicinal herb were superior to those of the purple skin, so it was more obvious and significant in treating diseases and health care. In addition, the taste of the candied sarcophagus was better. When chewing, there would be no obvious residue or fiber, while the purple-skinned sarcophagus would be a little astringent, with a lot of residue and would jam the teeth. In terms of price, the Purple Skin Stone Orchid was cheaper than the Iron Skin Stone Orchid. In summary, according to individual needs and health conditions, you can choose the medicinal herbs that are suitable for you to carry out targeted treatment.
There's often a character named Kyo in some Iron Release fanfictions. He's an orphan who discovers his Iron Release ability by accident when trying to protect his friends from a group of bandits. His unique take on Iron Release is that he can combine it with wind chakra to create razor - sharp iron shards that can cut through almost anything. Another interesting character is Mei. She's a female ninja who uses her Iron Release to create beautiful yet deadly iron flower constructs that can release poisonous spores.
Some fanfics might feature original characters. For instance, a young samurai from the Land of Iron who dreams of becoming a great warrior and befriends a ninja from Konoha. This samurai could be the main focus, showing his growth and how he bridges the gap between the samurai and ninja worlds.