In the anime:
Bartlow was first seen in the counsel chamber of Princess Alisha Diphda, following the enigmatic appearance of a thickening black cloud/fog over the nearby town of Gluriel. He advised Alisha that the city should begin conscripting soldiers from the participants of the Sacred Blade Festival (an event to find the man who can pull the Sacred Sword from the stone), much to Alisha’s disapproval.
Bartlow then put out word to assassins such as Lunarre and the group called the Scattered Bones that he was willing to pay handsomely for Alisha’s death, prompting the assassination attempts that take place throughout the first two episodes of the series. When two members (including Rose) of the Scattered Bones reported to Bartlow on Alisha’s activities, he called his princess a fool for refusing to defend against the amassing Rolance troops, claiming that her inaction and idealistic obsession with peace at any cost would result in innumerable civilian casualties. Bartlow also conveyed to them the urgency of their mission by falsely claiming that rumours exist of the princess secretly being allied to Rolance, convincing the assassins that Alisha had political gain by surrendering her people to the enemy.
The next day, Bartlow was seen watching the Sacred Blade Festival with immense displeasure, watching countless hopefuls fail to draw the sword from the stone. After none are chosen by the sword or by Lailah (the Lady of the Lake), Alisha elected to give a speech on the necessity of peace with Rolance and on the avoidance of war. This greatly angered the silent crowd, and their anger and their fear of invasion manifested in the form of Malevolence (a dark magic associated with Hellions, which was drawn out from the ruins under the city where it was concentrated). The Malevolence caused the sky around the church where the festival took place to turn black, and the flames that lit the inside to explosively put themselves out. It then formed into a giant, flying dragon-like monster (hellion), which attacked the crowd and the altar of the stone. The hellion was unable to attack the sword due to a magical barrier, but its flames still blocked the exit, trapping everyone inside the church. When Sorey (a boy who had spent his childhood living with seraphs (an invisible, powerful race of people much more like the sidhe from English folklore than their biblical namesake)) rushed to take the sacred sword in order to fight the beast, Bartlow’s assassin Rose sprung into action, and attacked Alisha with a fighting knife. Alisha was also skilled in combat, though her advisor Maltran still tried to join in to help the princess, only to be stopped by Bartlow, obsessed with watching Alisha die, whose excuse to Maltran was “The princess can protect herself, your priority must be to evacuate the spectators.” He issued the same order to the nearby knights in order to stop them from rescuing Alisha, but he was later smacked by the Hellion’s giant tail and thrown across the building.
While Alisha and Rose fought, Sorey drew the sword from the stone, was pronounced Shepherd by Lailah, and merged with Lailah, developing immense power, combat proficiency, and flight, allowing him to destroy the hellion with ease. Bartlow’s assassin was distracted from her fight with the princess by the sight of the hellion’s destruction, as was the entire crowd and Alisha, but once eyes returned to the princess, Rose slipped away and escaped. Bartlow sat in shock at Sorey’s power, declaring it impossible, though secretly desiring to have this power for himself.
The City Council, under Bartlow’s direction later unanimously voted that Bartlow should have custody and command over Sorey, but this decision was overruled by Alisha, much to his fury. Later, after the city was attacked by a dragon, Bartlow invited Sorey to dinner, before having his servant tell Alisha that her father had ordered her to provide medical supplies to ple plagued city of Marlind. After having dinner with Sorey and expressin his intention for the two to become friends, Bartlow ordered his men to prepare for war.
Some weeks later, Maltran and Sirel (a member of Alisha's personal cavalry) rushed to meet the princess in Marlind to warn her that Bartlow had been continuing his preparations for war by sending a batallion of troops to Glaivend Basin (along the Hyland-Rolance Border. Leading a small batallion to stop this act of provocation, Alisha brought Sirel and Sorey to head off the second batch of troops Bartlow was sending to the valley. Predicting her move, the night before the head-off, Bartlow sent 13 members of the Scattered Bones to kill Alisha. After some violent confrontation, Rose (the group's leader) engaged Alisha in a battle of philosophy, arguing that Alisha's non-aggression strategy would simply result in the deaths of her army and sow even more hatred into the land. Their argument resulted in Alisha deliberately grabbing Rose's hand and pushing the knife into her throat jus hard enough to draw blood, and asking Rose to kill her. When Rose understood the honour and sincerity behind Alisha's mission, and that Bartlow had deceived her regarding the rumours of Alisha being aligned with Rolance, she sheathed her blades. Alisha promised Rose that she would understand her mission if she went to the battlefield, before slicing Rose's mask in half with her blade, revealing her true face as a friend of Sorey's and a supposed mercahnt whom she had met previously. Rose then agreed to help Alisha's men by providing them with food on the battlefield, finally ending the alliance between the Scattered Bones and Bartlow.
Bartlow sent 20,000 troops, with 18,000 heading for the battle, and the remainder guarding the road. Alisha went with 1,200 troops (which Maltran warned might not be enough. He also kept 1,000 behind to ensure that he was properly protected. Bartlow's troops were led by General Landon. After the battle was stopped by Sorey, Landon was arrested for his treachery (after trying to kill the princess).
Bartlow later sent a battalion of knights to surprise-attack Alisha's company. They killed everyone but Alisha and Sirel, and a small band of Ian's company, as well as Maltran, who was captured. Believing that the attack had killed Alisha as well, Bartlow smiled upon receiving the report of the battle from a messenger. According to Ian, Bartlow had sent the troops after claiming that Alisha had betrayed and stolen from the kingdom of Hyland.
Later, Bartlow visited the King (who was worried about his daughter) and told him that Alisha hadn't been found but he was looking for her to bring her home, and claimed that the troops he'd sent to capture her and take her to him for execution were simply taking her to be escorted back to her father. The King was frail and dying, and expressed his desire to see Alisha one last time. Part way through their conversation, the King began to cough uncontrollably, forcing Bartlow to get the doctor to bring his medicine.Baltrow then visited the castle dungeon in order to mock Maltran, whom his men had captured, sadistically smiling as he asked her if she was going to feel at least a little guilt for her "crime against the state" (helping Alisha). Maltran refused to speak to Bartlow, or even look at him as he toyed with her emotions regarding the princess, until eventually she calmly told him "I don't need to be there for the princess or her fine warriors. She won't yield to you." Bartlow's response for this was that he would order his men to kill Alisha, before telling Maltran that the King believed in his daughter's guilt, and put him in charge of dealing with her. After Bartlow left, tears began to fill Maltran's eyes.
When Bartlow's knights found Alisha's company in a small town just outside Ladylake (which had just been attacked by a tornado-like hellion), they charged towards them without even stopping to help the injured prompting Ian to ask how they could even call themselves knights of Hyland, and launching arrows at them. However, all of Bartlow's knights were killed by a Hellion that was made of mud, which attacked them by forming a giant landslide. The Mud Hellion then attacked and tried to kill Alisha, but was shot and vanquished by the seraph Zaveid, using the pistol Siegfried a dragon-killing weapon. Later that day, Ian learned that Bartlow was having Maltran crucified in the town square, and in sheer horror rand to tell the princess and her company. The cross upon which Maltran was placed stated that she would remain there until Alisha surrendered herself to Bartlow. Sirel saw that Maltran was only being crucified as a lure to draw Alisha in, and warned Alisha that rescuing her friend would only result in their capture. Shortly afterwards, Alisha's long-time enemy, the hellion Lunarre arrived for an unexpectedly cordial conversation in which he expressed his disgust at Bartlo's actions, and stated his desire to have Bartlow thrown into the front lines of battle if it would stop his warmongering. When Alisha expressed a more pacifistic world view, Lunarre left in disgust.
More of Bartlow's men attacked Alisha's encampment in the night, and began stabbing the soldiers beds as they slept, only to discover that they were only stabbing pillows and that Alisha's men had left the encampment as it was as a distraction. Alisha and her soldiers then took the canals into the city, hiding themselves under their shields, before climbing using ropes onto a bridge, entering the city not too far from the square. However, Bartlow's men were waiting for them around the bridge, and even hidden within the tunnel they tried to use to escape. Alisha and most of her men managed to escape the arrows, and Bartlow deployed 1,000 more men into the city, before ordering his general to "light up the square." All of the torches surrounding Maltran were lit making it harder to rescue her, while Lunarre watched in ecstasy, finding what was happening extremely entertaining. Lunarre then leapt in front of the cross upon which Maltran was being crucified, and told her that Alisha was coming for her, before laughing at how entertaining the situation was for him. When Maltran told him that Alisha wouldn't be coming to the cross to directly rescue her, Lunarre was intensely annoyed, having waited in the wrong place to view all of the fun, and as a result he used blue flames to murder all of Bartlow's men who surrounded the cross.
Bartlow patiently waited for Alisha in his manor, only to realise after several hours that Alisha should have been there by now and must have been heading for the royal palace and not directly for him, Horrified by what Alisha might tell her father, he had his men prepare a carriage immediately, and made haste to stop her. Upon defeating the King's security, Alisha saw that her father was extraordinarily overcome by the Malevolence that he was emanating a red form of it. Still, the king told her how much she was starting to look like her mother.
Before Alisha could tell her father anything, and still horrified at what he was becoming and in a state of shock, Alisha was put in an even more devastating position when Bartlow arrived in the royal chamber, saying "I never imagined that you would target your father like this.Getting the leader of the enemy is the first rule of war." Bartlow wanted the king to believe that Alisha was there to assassinate him, despite her counterclaims. After continuing his accusations, Bartlow pulled out his sword and attempted to personally murder Alisha, who was able to dodge his strikes, until her father got in the way and was accidentally stabbed by Bartlow.
Despite accidentally killing his king, Bartlow showed no remorse or dissuasion from his task, and instead demanded that Alisha pick up her sword. Alisha rebuffed him, telling him that she wouldn't kill him no matter what and that he would spend the rest of his life in jail for the murder of the king. When Bartlow told her that the people would be more likely to believe him, a trusted and well respected official, than her, a princess who squanders public money on idealistic crusades, and promised to launch an immense propaganda campaign against her, Alisha called Bartlow's men in from outside, and they stared at him in horror, seeing the blood on his sword and the king lying there dead.
After trying and failing to explain himself to his devastated soldiers, who were furious at him for having lied about their cause, Bartlow ran to the palace balcony in desparation. When he was pursued by Alisha, he finally asked "Alisha, you still won't kill me, right?" When she answered "No", he smiled at her and said "Then I win!", before leaping from the balcony to his death. Bartlow's former soldiers then released Maltran, though the city was almost immediately set upon by a dragon.