In Episode 8 at the city of Tetras, Dartagnan is shown to be prone on crying for being too scared while trying to fight against a bear trouble monster in the city as it attacks him. He was later saved by Bucky by throwing his spirit, Jibac in explosion which he was revealed to be standing on the roof in front of him. Bucky also looked at his G.C. watch where he found the trouble monster attacking the area as he goes down the roof to confront him. Dartagnan also notices Jibac which he recognizes Bucky as the G.C. as he introduces himself with Pinky and Kai much to his joy and happiness and wants to be taught how to fight against the monsters in their town.
They entered in their estate as the door was shut causing both Pinky and Kai to be scared and behind them as Dartagnan's butler which he was calling him as young master and the arrival of Dartagnan's spirit, Conde Bucklet or simply as Baklet. Pinky becomes angered while grabbing Dartagnan's spirit as his mother arrives to see them as she grabs Conde Bucklet to the ground which she teaches it to become spoiled and Dartagnan was angrily dismayed by her actions as his mother tells him to introduces himself to the group as well as his spirit even he introduces to them as well. He tells Bucky that he wanted to learn how to fight which the latter refuses and Dartagnan wanted to fight like they do which they agreed. At the gardens he was trained by the group in how to fight theTrouble Monsters which Dartagnan is trained by Kai first and soon to be chased by a Sabertooth Trouble Monster instead of being brave enough to fight it which makes him get hurt. When he was trained by Pinky, she tells him to pick between the two boxes. Dartagnan picks the right box as the jack in a box beneath the box causing him to get scared which he picks the wrong box and the correct box is on the left much to Pinky's disappointment. Although, Bucky knows that the correct box is also the same as in the wrong box which makes Pinky became dismayed by her own teachings. This time, Bucky tells him to overcome his fear as he points out the ballfire as he makes Kai an example where he goes into the ballfire as he survives.
Dartagnan becomes saddened after Bucky's remark of how come he's going to be a G.C. of Tetras if he didn't overcome his fear. Later, he stabs three leaves from his rapier much to the happiness to his mother and the surprise of Bucky and his group. Dartagnan also tells them that he is expert in fencing with the use of the rapier. Bucky also wants to know about his father which he replies that he died. After his butler explains to Bucky and the group about how he grieves his father's death and he mourns while staying at his father's grave.
At the haunted house, Dartagnan now trained by Bucky to fight haunted creatures as he almost got hit from its attack while being watched by Pinky, Kai and his butler. Pinky uses her Pink Miracle Bomber to disperse the haunted creature with its light. The haunted creature reveals to be a Dark Knight which is confronted by the group and Dartagnan notices the sword it was wielding was coming from his late father's and knowing it was his father as the Dark Knight begins to attack Kai as Kai does the same while clashing with their weapons. Dartagnan wanted to stop his father but was later saved by his butler after the Dark Knight attempts to hit him with a spiritual blast.
Dartagnan begs Bucky to stop the Dark Knight which he refuses and he angrily tells him that he has to fight and to overcome his fear and all the people including his butler are risking their lives for him. With no other choice, Dartagnan stands up and decided to fight the Dark Knight as Bucky instructs him how he trained earlier as the Dark Knight attempts to hit with several spiritual blast as Dartagnan manages to repel several of them with his rapier finally overcome his fear. The Dark Knight manages to destroy his rapier but Dartagnan retaliates by knocking its sword with his broken rapier and he grabs it. His spirit Conde Bucklet reaches the edge of his late father's rapier which it decides to aid him and Dartagnan manages to defeat the Dark Knight by thrusting with his late father's rapier with his spirit blown in explosion. The Dark Knight turns out to be a cowardly nine-tailed fox as it runs away in fright. Dartagnan is later seen being hugged by his father's spirit with white wings on his back knowing that he becomes his father's successor before he flew away in the sky in a flash of light and his mother watches him after overcoming his fear which she cries after seeing her late husband again.
After the incident, Bucky bid farewell to Dartagnan which he tells him that he has to be brave and to protect his town in Tetras as he agrees while donning his father's outfit.
During Episode 25, he was seen fighting against the shadow versions of Slash and he is among the others from different islands are frozen in solid at the hands of Spaak's sister under Slash's possession and later in the final episode where he along with fellow Great Children are reunited in the final battle against Slash.
Dartagnan has a very long green hair with a full fringe and is tied in a low ponytail with a yellow ribbon is embedded on his ponytail and blue eyes.
His primary appearance is a purple collared military tunic with yellow linings and the buttons are ribbon shaped similar to a Cheongsam and a black belt which is tucked into his tunic, white pants and light brown triangular shaped and brown warrior boots.
In the end of Episode 8, Dartagnan dons his father's musketeer outfit, is a high-neck blue musketeer uniform with long popped up sleeves and a white belt which is tucked into his uniform, white pants and brown thigh high socks. He also wears brown gloves and a white collared cape with a jewel in the center of his cape and also wears a sky blue musketeer hat. He has a white sword sheath where he keeps his late father's rapier at the left side of his waist.
Dartagnan is described as a calm and very determined kid but is also more prone to crying due to his fear in fighting against large Trouble Monsters in his hometown as a G.C. of Tetras. By the time Bucky tells him to face his fear as he successfully overcomes it. He is shown to be a brave and confident kid as seen where he fights the Dark Knight all by himself and he manages to defeat it. When his father is mentioned in Episode 8, he shows his grief where he still mourns his father in his grave showing that he loves his father more than his mother as seen after he defeats the Dark Knight he hugs his father in his spirit form showing his love and affection towards him.
So far, Dartagnan's abilities are shown in Episode 8 which he is expert in fencing and wields the rapier. He later uses his late father's rapier and was aided with his spirit to make a devastating straight thrust in explosion.
- Dartagnan is the youngest G.C of the anime series.
- After Bucky pushes him away and has to overcome his fear, Dartagnan is shown to be serious and angry but having tears from his eyes due to being prone on crying.
- Dartagnan's fighting style is Fencing.
- Dartagnan's father is possibly the previous G.C. of Tetras before him.
- His estate in Tetras is based on James' estate in the episode "Holy Matrimony" from the anime Pokemon.
- In the Japanese version of the anime, He is voiced by Tomoko Ishimura. But in the Filipino Dub, He is voiced by Jefferson Utanes who also voices both Kai and Ali Babah in her young gay form.
- In the Filipino Dub of the anime, he is renamed as Tartanian instead of his original name.