As a Hollow, he was quite large and bulky, making Tier Harribel look very small in comparison. His body was a dull purple with a white neck. His head sprouted out like that of a hammerhead shark and he had two rows of 8 teeth with no eyes on his head. He had two gills on each side of his chest as well as fins for arms and two bulky legs. His Hollow hole was located in the center of his chest.
Once turned into an Arrancar, he slimmed down quite a bit, taking on a more humanoid appearance. His signature hammerhead protrusions remain but he gains normal hands with small fin like protrusions over his hands. His Hollow hole moves down to his stomach and his entire chest becomes white in color. He retains the slash in his head given to him by Harribel while he was a Hollow. His gills move to his neck and all his teeth move to a single row on his head with a normal mouth below.
As a Hollow, he was arrogant and subservient to Baraggan, telling the stronger Harribel that she had no choice but to serve Baraggan. Once an Arrancar, his arrogance grows, believing himself to be better and stronger than Harribel. He becomes obsessed with power, believing he will join the strongest ranks in Hueco Mundo. Even when his Hierro is pierced, he simply laughs and continues to say that his power was so much greater.
As Tier Harribel talked with Baraggan Louisenbairn, she was presented the option of either joining him or going to a place where he cannot see her. A Hollow then, the Hammerhead Arrancar approached her and said she had no choice but to become subservient to Baraggan. Harribel told him not to touch her and sliced his head open, causing him to fall backwards while panicking. Baraggan then told her she will regret striking one of his subordinates as she walked away.
Now an Arrancar, the Harmmerhead Arrancar broke into Harribel's hide out. Emilou Apacci noted that his mask was cracked and figured he was an Arrancar. He went to attack Apacci, utilizing sonído to move to her. As he struck though, his attack was blocked by Harribel. He told her it had been a long time and she then began to remember him as the Hollow she attacked before. He told her that she made him look like a fool before and then raised his reiatsu as he continued to push against her sword. He asked her if she could understand his transformation and then pushed her back against the wall. He then walked to the three others and said he had not forgotten about them, charging and then firing a Cero at them. However, Harribel stepped in and knocked his arm up, saving the others. Harribel then told them to run and the Arrancar said that she was beginning to understand the difference in their power. He told Harribel that he only wants to kill her and did not care for the others.
Having overpowered her, he tossed Harribel outside. He then reminded her that Baraggan told her that she would regret attacking him. He then said that Hueco Mundo would undergo a big change and he would defeat all nuisances like Harribel before joining the top ranks. He then generated a lance and tried to stab Harribel but Apacci, Sung-Sun and Mila Rose re-appeared and attacked him. He cursed them before Apacci told him they would do anything for Harribel, even sacrificing themselves. They attacked him once more but failed. He taunted Harribel once more before she attacked again without effect but quickly struck again, throwing him off balance. He stumbled around before Harribel hit him with another powerful strike, finally piercing his Hierro and creating a crater. However, as the dust cleared, he revealed he was not phased and once more threw Harribel. He jumped up and struck her in mid air, sending her crashing. He attacked again, nearly killing Harribel before Sōsuke Aizen stopped his attack and cut across his chest, killing him.