WARNING: Beware of major uncovered story spoilers!
- Amnesiac Hero: He reveals early on that he doesn't actually have any memories from before the accident. He just knows he's Harry's Pikachu from what he's pieced together from everyone else's conversations. Tim noted that Pikachu was a lot cuter and more docile before the accident.
- Badass Baritone: Has a surprisingly deep voice, especially by Pikachu standards. The Badass part is somewhat subverted by his inability to use moves, but he's still very brave and will go through hell and back to find the truth.
- Badass Normal: He can't use any moves, so he just relies on his own wits and physical prowess to save the day. He does end up using Thunderbolt to put a stop to Noivern by the end however.
- Casanova Wannabe: Has a weakness for beautiful human women. He's prone to winking at them and asking them on dates.
- Curious as a Monkey: He pokes around places to see how things work and once tried to look under a Mimikyu's disguise. He winds up screaming in terror.
- Eureka Moment: He punctuates each one with an appropriate Catchphrase, "A bolt of brilliance!"
- Great Detective: Apart from being a one and a half foot tall electric rodent, Detective Pikachu is the character archetype.
- Intelligible Unintelligible: He's perfectly capable of communicating with humans, but only to Tim, for some reason, with his deep, gravelly voice coming out as Pokémon Speak to everyone else. It also works the other way around, with Pikachu translating the testimony of other Pokemon.
- Nice Hat: Wears a Sherlock Holmes-style deerstalker cap. It's a Tragic Keepsake from his former trainer, who went missing after a car crash.
- Nonstandard Character Design: Lacks the Cat Smile Pikachu usually have.
- Pokémon Speak: Only Tim can understand him, with his voice towards him being entirely in English. Other people just hear Detective Pikachu talking like other members of his species, leading to a deliberate and comedic use of Vocal Dissonance.
- Rule of Cool: Word of God states this Pikachu drinks coffee because it's one of the other things that goes with the image of a cool sleuth (the other one was smoking a pipe, but that had to be dialed down for younger audiences). For an in-game explanation, the mystery is still there by the end of the game.
- Speaks Fluent Animal: Naturally, being a Pokémon himself, and akin to the ones in Pokémon Mystery Dungeon series, Detective Pikachu is able to converse with other Pokémon who can't speak human. This is a major factor in how he solves cases, being able to get information out of them that others can't.
- Sweet Tooth: He tends to eat all the sweets laid out for clients in the Detective Agency, much to Amanda's annoyance.
- Talking Animal: Is a rodent that can speak to humans. Well, one human, it seems.
- Trademark Favorite Food: Loves coffee. He knows a great deal about coffee, has a favorite café, and will tell Tim what he enjoys about different blends.
- Uniformity Exception: Detective Pikachu looks exactly like any other Pikachu. Tim can only tell them apart by Detective Pikachu's unusually deep voice and his deerstalker cap.
- Unnecessary Combat Roll: He occasionally does one in personal skits. "Just in case."
- The Un-Reveal: You never find out why he can talk to Tim only, why he can't use any moves, or why he is so knowledgeable about coffee and likes drinking it. It's heavily implied he's connected to Tim's father in some way, but how or why is never explained.
- Uplifted Animal: He always moves on two legs, even when he's running. Detective Pikachu also can't use any moves, or discharge electricity very well.
- Vocal Dissonance: A Pikachu with a deep, manly voice. Even his Pokémon Speak is still in this voice.
A young (possibly teenaged) boy who arrived in Ryme City for clues regarding his father, who has not been seen for the last two months.
- Disappeared Dad: The whole reason he decides to investigate his disappearance.
- Diving Save: Pulls one to save Pikachu from Glalie.
- The Everyman: Much like protagonists in other games, Tim is only kind of average. So he serves as a good foil for the extremely unusual titular character, Detective Pikachu.
- Extreme Doormat: Tim has problems saying no and often just goes along with what everyone else is doing, unless it's clearly illegal.
- Generation Xerox: His skills as a detective are said to be on par with his father's, though no one else knows Pikachu does a lot of work as well.
- Just a Kid: Mike Baker worries for Tim's safety and tries to dissuade him from investigating Harry's disappearance until Tim proves himself as a detective, with a little help from Pikachu of course.
- Nice Guy: Tim is reservedly cheerful and outgoing enough to help anyone he can with his sleuthing skills.
- Only Sane Man: He constantly has to reel Pikachu in whenever his imagination or love for coffee gets the better of him.
- Punny Name: He's a good young man.
- Red Is Heroic: Wears a red hoodie and is the human protagonist of the game.
- Talking to Themself: Since other people can't understand what Pikachu is saying, other people believe he's doing this.
- Vague Age: He looks like a teenager, but it's uncertain what age he is. He is old enough to drive a car and be accepted in university, so he may be Older Than He Looks.
Tim's father. A skillful detective who went missing looking into the Pokémon rampage incidents in Ryme City.
- Disappeared Dad: But of course. Tim is unable to find him at the end of the story, but Mewtwo assures Tim his father is still alive.
- He Knows Too Much: He was targeted by the Big Bad because he was getting very close to uncovering the truth behind the R chemical incidents and was taken out by tampering with his car.
- The Un-Reveal: His disappearance is never solved.
The detective agency chief and a good friend to Harry. His partner is Accelgor.
- Flash Step: Accelgor moves so fast that it almost seems like it's teleporting from place to place.
- Reasonable Authority Figure: As head of the Baker Detective Agency, Mike's initially worried about Tim's safety in regards to getting involved in the case of his father's disappearance, but comes around when Tim proves himself as a capable detective. He has Accelgor accompany Tim and Pikachu to the warehouse for extra assistance and it proves helpful in the investigation many times.
The detective agency assistant and secretary. Her partner is Fletching.
Chief inspector of Ryme City who investigates the Pokémon incidents and Harry's disappearance.
A new assistant director working for GNN.
- Contrived Coincidence: The many times Tim and Pikachu bump into her makes the latter think it must be destiny...for her to be Pikachu's girl.
- Ship Tease: A few comments from others try to paint her as Tim's girlfriend. Only Tim seems to fall for her, but she isn't aware of it.
- Those Two Girls: With Meiko.
- Two First Names: Christie isn't exactly a last name. Except for one very famous writer and a former Governor of New Jersey.
- Tomboy and Girly Girl: The Girly Girl to Meiko's Tomboy.
An energetic TV director and senior to Emilia.
- Action Girl: Goes with her Intrepid Reporter status.
- Going for the Big Scoop: This woman doesn't let a rampaging Charizard convince her to run away.
- Intrepid Reporter: Highly passionate about filming anything remotely dangerous.
- Skewed Priorities: Again, she didn't flinch or scream when she taped the rampaging Charizard. She was thrilled to stay there and film the start of the chaos, unlike how Emilia wanted to flee.
- Those Two Girls: With Emilia.
- Tomboy and Girly Girl: Tomboy to Emilia's Girly Girl.
The barista at the Hi-Hat Cafe. His partner is Ludicolo.
- Genki Girl: Pablo's Ludicolo is female and like all Ludicolo, she loves to dance. Unfortunately she has a habit of dancing when serving, causing drinks to spill.
Meiko's boss and TV producer at GNN. A proud man happy to have reliable workers.
- Big Bad: He's the true mastermind behind the distribution of R.
- Bitch in Sheep's Clothing: Portrayed as a nice person among his associates. His true personality is quite cunning.
- Breath Weapon: His Noivern fires a purple-blueish beam from it's mouth to defend against (changing from a sonic wave attack to use the breath attack) Pikachu's Thunderbolt at the end of the game.
- I Never Said It Was Poison: What linked him to being the Big Bad was casually telling Tim to be careful since Pikachu can't use any moves - a fact he was never told about before - during the carnival in Chapter 9.
- Make Me Wanna Shout: At the end of the game he has his Noivern release sonic waves to destroy a tank that contains R, which also harms Tim, when he moves in front of the tank.
- Man Behind the Man: He is the real Big Bad of the story and behind the R incidents, ordering Keith to be the face in exchange for money compensation.
- Walking Spoiler: His identity as the main villain.
The president of GNN and boss of everyone working there. Highly passionate about reporting news.
- Corrupt Corporate Executive: Invoked. The fact his nice attitude drops the moment accidents happen on the set make him change gears quickly. This was even more invoked in Chapter 9, but he really wasn't corrupt.
- Red Herring: Once evidence about the carnival's shootings were produced after Keith fled GNN, Graham is suspected to be the Man Behind the Man behind the R incidents (and even Meiko would have believed it was him), but he is ultimately innocent.
- Skewed Priorities: He's basically a male version of Meiko when it comes to focusing his attention of possible big scoops.
The current head of PCL, succeeding the previous head.
A staff member of PCL, who works with his partner Garbodor in recycling garbage to use for his purification research. Shares the lab with Nina.
- Big Fun: The largest and most excitable member of PCL.
- No OSHA Compliance: If his machine isn't working the moment he uses Garbodor, the lab ends up with a stinky smell Nina has to endure.
- Walking Wasteland: Fridge's partner is a Garbodor. It likes working at the facility since it gets fed trash all day.
A staff member of PCL, who works creating medicines and concoctions for Pokémon using the help of her partner Shuckle. Shares the lab with Fridge.
A staff member of PCL, who works with engines together with his unreliable partner Rotom.
An aggravated staff member of PCL wary of newcomers and other members in general, who works with his partners Solosis and Duosion.
- Red Herring: Due to the nature of what he studies and his general personality, you're led to believe that he's the one who produced Chemical R, but he isn't.
- Surrounded by Idiots: He used to be more open to his colleagues and other people until he had bad experiences with newbies working at the lab, so much that he causes issues with the others by changing the password lock to the yard.
The receptionist working at PCL who also acts as a security guard of sorts. Her partner is Floette.
- Cuteness Proximity: She is initially indifferent toward Pikachu apart from a quick downward glance when he and Tim first arrive at PCL. When both of them return later, Rita apparently loses the will to resist and plays with a surprised Pikachu.
- Small Role, Big Impact: She doesn't have an outstanding role to play unlike her colleagues, but she provides the duo a recording that shows the culprit behind Trevenant going nuts.
A wealthy resort developer wishing to build a resort in Cappucci Island. Her partner is Spritzee.
- Corrupt Corporate Executive: She endangered the habitat of local Pokémon by releasing a rabid Crawdaunt in the lake and went a long way to frame Waals for it just because his house was in the way and he wouldn't agree to be relocated.
An aspiring Pokemon Ranger who is dedicated to helping Pokemon in need. Dr. Waals' protege. He has no partner, but he is good friends with a Feebas at the lake.
- Androcles' Lion: Feebas. When first encountered, Feebas is weakly floating in water on the Hidden Path, and after Milo gives it a potion to heal it, they accompany them. In the confrontation with Crawdaunt, it jumps out of the water to save Milo from a savage blow, and then evolves into a Milotic powerful enough to drive Crawdaunt away.
- Friend to All Living Things: Comes with his aspiration. Always eager to help Pokémon in need.
The former head of PCL who retired from experiments following the incident at the facility and now resides in Cappucci Island.
- It's All My Fault: Regarding the incident at PCL while he worked there and the creation of Chemical R.
- Unwitting Instigator of Doom: His research into using Mew's gene to create a vaccine to help Pokémon ended up being the birth of Chemical R using the wrong gene - Mewtwo's Berserk Gene - that resulted in the first PCL building's destruction by its rampaging Pokémon and pretty much the whole reason the story is even happening as the basis for the vaccine was stolen.
Frank Holiday's apparent reliable police force partner who is quick to jump to conclusions and can't stand people trying to prove his facts wrong. His partner is Manetric.
- The Nose Knows: His Manetric has a very keen sense of smell that he is able to detect any faint smells very well. He can even detect the gaseous state of Chemical R in balloons and avoid being affected by it.
- Plot Allergy: His Manetric is allergic to Louise's Spritzee's smell whenever he smells it. It ends up becoming the final decisive evidence connecting Louise to the Crawdaunt at the lake.
- The Rival: Towards Tim and Pikachu.
- Teeth-Clenched Teamwork: He has no choice but to assist Tim and Pikachu during Chapter 9 to rout out the spots that contain Chemical R in the carnival route.
- Small Name, Big Ego: Brad is very much defiant in his thinking that he will not accept anyone else trying to refute his claims and will stick to them if the proof isn't decisive enough.
A rising violinist star who performs using a very valuable violin with her partner Kricketune at GNN.
- Like a Daughter to Me: How her Kricketune sees her.
- MacGuffin: The violin she has was made by her late grandfather, who was actually a very skilled craftsman in prized instruments, making her violin a one-of-a-kind rarity that can go up to 2 million dollars in value though she isn't interested in selling it as it is a memento from her grandfather. But then it gets destroyed in a set accident by someone. Then it's revealed the violin that got wrecked was a fake and swapped to make everyone believe it was gone for good.
- Shrinking Violet: She has to deal with being on TV... and Olga.
A scatterbrained assistant director working for GNN. His partner is Skorupi.
- Big Bad: He is the leading cause of Chemical R incidents in Ryme City and the one who attacked Harry at Fine Park. Except he is not the real culprit and is working for someone else.
- The Klutz: He often messes up on the set. This is all but a big ruse.
- Obfuscating Stupidity: As part of the ruse as his assistant director persona.
- Only in It for the Money: His entire motivation on spreading Chemical R.
- Walking Spoiler: The fact he is the main bad guy AND the fact someone else is controlling his moves.
The director of GNN. His partner is Hoothoot.
- But Not Too Foreign: Not as much as Meiko, but his last name is more American's sounding.
A comedian and co-host to Olga in Maximum Music. His partner is Chatot.
- Butt-Monkey: His Chatot apparently doesn't have a high opinion of him and often makes fun of him for real. Even when Max is found out as the culprit, Chatot can only say "Admit it! Admit it!"
- Hidden Depths: Chapter 8 reveals he was planning on selling the violin in the black market auction aboard the S.S. Prime Treasure.
- Polly Wants a Microphone: Max's Chatot is an extremely adept mimic who can imitate other characters on command from cues. This becomes important in proving he is the only without an alibi to stealing Carina's violin behind the set.
- Tragic Villain: Stealing Carina's violin to sell for 2 million dollars as a backup plan for his apparent termination in GNN was all for nothing when he was told the executives never, ever wanted to fire him despite his low ratings.
The other co-host of Maximum Music and a general horror to anyone who ever gets to talk to her outside the shows. Her partner is Purugly.
- Doting Parent: Towards her prune Purugly.
- Nice Character, Mean Actor: On her show, she is pleasant. Outside the show, everyone wants to avoid her wrath like the plague.
- Red Herring: She constantly harassed Carina about wanting her violin and knew that her violin was a prized artifact that could be sold for 2 million dollars, but she is completely innocent in the case to find it.
A man working at a warehouse in Ryme Wharf who is put in charge of the production and shipping of Chemical R.
- Badass Normal: Was prepared to fight Accelgor with nothing but his bare hands.
- The Brute: Alexander is a burly man who happens to be employed by whoever is in charge of the whole operation.
- Distracted by the Sexy: The Machamp who work at the wharf can't forget him...all because he has a stunning physique.
- Violence Is the Only Option: It's said that this is best solution for any problems.
Dr. Waals' former lab assistant. He was kidnapped by Keith and forced to create more R samples at Ryme Wharf for months. His partner is Pansage.
- Distressed Dude: Being the other person who knew how to make Chemical R, he was abducted and forced to make it for months while trapped at a warehouse in Ryme Wharf.
A world renowned chef in the S.S. Prime Treasure for an interview with GNN. He has no partner, but later it turns out he actually does and it's Kecleon.
- Supreme Chef: A world renowned chef who is in the process of replicating lost recipes from the Henry Brothers. He gave up on trying to do it that he decided to steal a valuable mask to avoid heavy spending losses trying to buy their genuine - yet stolen - recipe book from the black market aboard the ship.
An elderly woman and passenger in the S.S. Prime Treasure who is the victim of switched luggage. Her partner is Snubbull.
Captain of the S.S. Prime Treasure, although he doesn't exactly own the ship and doesn't know what happens in it since the passengers are the actual owners. His partner is Nosepass.
- Expy: Of the Mewtwo from Pokémon: The First Movie. It has a mellow, masculine telepathic voice, serves a major antagonistic role due to its mistreatment at humans' hands, and uses Shadow Ball as its Signature Move.
- Humans Are the Real Monsters: It's basically any Mewtwo's thoughts on them at this point. It does acknowledge people like Tim are still worthy of...not being massacred by its hands.
- Kill 'Em All: Its very low opinion of humans is what nearly drives it to killing everyone at Ryme City.
- Olympus Mons: One of the few Legendary Pokémon to appear in the game, it is a major focus of the game's story in the retail/international release.
- Red Herring: He is hinted to be the one responsible for brainwashing the Pokemon rampaging through Ryme City. Ultimately, he turns out to be an Unwitting Instigator of Doom, as his body was used to create the chemical R, but his Berserk Gene was what caused Pokemon to go crazy. While Mewtwo remains vicious and dangerous, he is in fact a victim of the true Big Bad.