Originally introduced as Hato Higashikata's boyfriend, he is later revealed to be a Rock Human and the head of the smuggling cartel in the Locacaca Organization. After his henchmen have been killed, he infiltrates the Higashikata House and attacks the entirety of the Higashikata Family.
Tamaki Damo claims he is 23, though he appears much older, seeing as his hair is styled into a comb-over to hide his bald spot. His facial hair is styled into a goatee and horseshoe mustache. He is introduced wearing aviator sunglasses and a dark-colored tracksuit with spiked sleeves and an image of a saxophone on the left breast. He is much shorter than Hato and is considerably overweight.
Damo is introduced as an awkward but polite individual when he meets the Higashikata family, notably mumbling while speaking to Norisuke IV and Joshu. This is later revealed to be a facade hiding a much colder and calculated personality, which he unveils while interrogating Norisuke.
Not much is seen of Damo's everyday activities, but he takes running the Locacaca trade seriously, meticulously ensuring that it goes unnoticed and taking swift and ruthless action when it is threatened in any way. His interest in the profit a Locacaca hybrid will bring him even on the verge of death indicates that he does it out of greed.
His power having limited range, Damo's modus operandi is to infiltrate a place where his targets will be trapped in, then plant Vitamin C's handprints all over the place so that everyone will be melting and powerless. Damo enjoys lording over his victims, ordering them around in his position of power but goes rather straight to his point, being focused on his objectives. He also sadistically tortures and humiliates his victims, inserting various common-place objects into them and once videotaping it for his own enjoyment. In contrast, Damo has a tendency to "spare" one of his victims for various reasons, such as self-punishment for being careless or excessive cruelty. Damo has also a penchant for cutting off limbs with a 1,000 yen bill if they do not comply.
Tamaki Damo has a short temper, regularly letting out short bursts of anger accompanied by a similarly violent action and insults. Being underestimated, even remotely, such as thinking that keeping information is being hidden or seemingly playing dumb, enrages him. However, he can acknowledge one's merits rather easily, praising Kira and Josefumi for managing to steal a Locacaca branch.
Damo is manipulative, seducing Hato with the specific purpose of approaching and interrogating her family and had no qualms with torturing and killing them all, including Hato herself. He has a habit of exploiting possible pressure points such as Josefumi's fundamental lack of interests in helping Yoshikage Kira and Hato's affection for her father to gain leverage or an advantage in a fight. He has also shown to be cowardly when his life is truly threatened, begging Hato to spare him and trying to convince Josuke they should team up.
- Main article: Vitamin C
Damo's Stand Vitamin C enables him to "soften" human bodies to turn them into something as malleable as putty or as viscous as liquid.
He then takes advantage of his victim's softened state to torture them for information or kill them outright. He typically cuts them with 1,000 yen bills or other thin objects.
On one occasion, Damo even inserts a living fish inside his victim's body and watches it swim.
Damo was born as a nameless Rock Human, and subsequently stole the name "Tamaki Damo" from some hapless human. He subsequently set shop at a cleaning shop named "Damo Kan". At the same time, he led his men in the Locacaca Organization, using it to sell the Locacaca to a handful of wealthy people for a hefty price.
On August 19, 2011, Tamaki Damo and his accomplice Yotsuyu Yagiyama stow aboard Yoshikage Kira's ship and ambush both him and Josefumi Kujo. Kira attempts to stop Damo with his Killer Queen, but Vitamin C softens Kira, Josefumi and their Stands. Damo reveals that he's aware of the duo's plan to steal and graft Locacaca Branches to grow their own fruits. He informs Kira that after the two stole the branches, Damo and his men searched for four months straight to find the culprits. Damo proceeds to interrogate and torture both Josefumi and Kira on the ship, trying to gain information as to their motives for stealing from him. He then states that the one who tells him the truth and betrays the other will be spared. After Kira and Josefumi escape, however, Damo furiously orders his men to search for the two and kill them, not knowing that Kira is already dying from the interrogation/escape and Josefumi is about to be fused with him due to the Wall Eyes.
After all of his men were killed in short order, Damo decided to confront the Higashikata Family. During a photo shoot in a studio next to Damo's shop, he approached Hato when one of the necklace she was wearing broke. Damo picked up all the pieces and repaired it, offering the necklace to Hato. Moreover Damo managed to write the sentence "I Love You" on the necklace, and Hato was seduced by the incredibly romantic gesture and he became her boyfriend. During their short time together, Damo and Hato had sex twice and bathed together five times.
Assault on the Higashikata
- Main article: Hato Brought Her Boyfriend Home (story arc)
- Main article: Vitamin C and Killer Queen (story arc)
In the present day, Tamaki Damo is introduced as Hato's boyfriend, and from Daiya's explanation to Josuke the first she has ever had or brought home to meet her father. Everyone is taken aback by his appearance, aside from Joshu, who is humored by him and even snatches the man's sunglasses off of his face and undoes his comb-over in reaction to his nervous mumbling. Damo presents Norisuke IV with a box of chocolate yokan he bought from the store near his cleaning company Damo Can Cleaning, while Kyo Nijimura and Norisuke IV notice that his fingerprints are left behind on things he has touched and are sticky and wet to the touch, suggesting that he also has a Stand. Nijimura also sees several clawed hand prints left behind him in the entry way, and Joshu is too amused with his family's guest to notice the fingerprints on his own arm.
Upon looking for info about Josefumi, Yasuho discovers his I.D. with a picture of Damo. Shortly after, his Stand becomes hostile, melting Kyo and Joshu away into the walls and a sink drain respectively, their fates currently unknown. After Daiya is affected by his Stand while trying to give the fax sent by Yasuho to Josuke, Damo convinces Hato to go look for her. Due to now being alone with Norisuke, he immobilizes the latter with his Stand and explains his motives.
Dropping his awkward demeanor, Damo states that he entered the home in order to solve three problems at once. For his first goal, he plans on discovering and eliminating the culprit behind the disappearance of four of his acquaintances: an architect, two twin brothers, and a security guard. Damo comments that the Wall Eyes have changed the landscape greatly, and wonders what could have happened to the whole family, which upsets Norisuke. Damo then asks if Norisuke knows anything about the Locacaca, which he refutes. Following this, Damo asks if he's killed Yotsuyu Yagiyama. Norisuke doesn't answer fast enough and Damo cuts off his left arm with a 1,000 yen bill. Norisuke admits to having killed Yotsuyu, however Damo thinks that Norisuke wasn't the only culprit in Yotsuyu's murder and asks who was with him.
Norisuke continues to feign confusion when pressed with more questions from Damo, but is tortured further as Damo has a fish flop about in Norisuke's liquefied body. It isn't until Damo threatens to murder the entire Higashikata family with Hato being killed in front of him that Norisuke cracks and confesses what he knows about Josuke's connection to Josefumi Kujo. Josuke then confronts Damo, demanding that he free the Higashikatas. Once a tearful Hato also approaches Damo, he melts her and rushes Josuke with Vitamin C. Soft & Wet is revealed to have planted bubbles on Hato, allowing her to escape from Vitamin C's liquid prison. Damo renders Josuke's body into a puddle using Vitamin C; preparing to kill him until he is attacked from behind by multiple spikes. Hato reveals herself as a Stand user and proceeds to viciously impale Damo using multiple spikes fired from her body, all while crying over Damo's betrayal. Damo, now terrified by his girlfriend's unknown powers, attempts to bargain for his life, insisting he was just joking and still loved Hato as she climbs a wall using her Stand to confront him.
Damo, now seriously wounded hurries to the fireplace while Hato scales the house. He berates Hato under his breath while gathering the liquefied Norisuke and shoving him into the fire pit. Damo hopes Hato will attempt to save her father from burning to death and in the process, touch Vitamin C's fingerprints. However, Josuke's bubbles reveal his location, allowing Hato to fire her Stand's spikes through the roof and into Damo's skull. The attack leaves Damo fatally wounded and damages Vitamin C enough to turn everyone that was liquefied back to normal. Damo flees from the house while trying to escape the Higashikatas, but runs into Josuke on a sidewalk. Damo once again tries to bargain for his life, offering to become Josuke's ally and supply him with Locacaca fruits to help his mother. This ultimately backfires, however, and Josuke swiftly delivers a punch to Damo's head; killing him as his body crumbles into rubble.
- Damo's last name is derived from Damo Suzuki, the former vocalist of the band, Can. The first name "Tamaki" was chosen as a reference to the band itself as the kanji can also be read as "Kan". This reading is also reflected in the name of Damo's cleaning service.
- Several aspects of his appearance and backstory are based on the character Irving Rosenfeld from the 2013 movie American Hustle, as Damo shares a very similar body build, hairstyle and pair of sunglasses with him. His occupation of owning a dry cleaning service and having committed identity theft are both also shared between the characters.