You can’t fight shadows if you don’t have your Pokemon with you.
Even though they are different in many ways, Persona and Pokemon are similar in how they are played. One of the most interesting things about the Persona games is how the Persona of each party member helps you understand them better. Persona 3 Portable is the same way.
You can see the same thing happen with some Pokemon characters, though not as much. There are a lot of Pokemon, so there are probably some that go well with the characters in Persona 3 Portable. Personas aren’t picked, but if they were, the cast would probably pick these Pokemon to go with them.
Makoto Yuki & Umbreon

The main characters in Persona don’t say anything, but their auras and styles show who they are. Makoto seems so calm and collected that he could be mistaken for a stoic.
Umbreon‘s attitude and style are reflected in his sleek black appearance. Persona 3 also has a lot to do with Midnight and the Moon. Umbreon works at night and gets its power from the moonlight, so Makoto should take it with her. Even the way it evolves requires nighttime or a Moon Shard.
Kotone Shiomi & Sylveon

In Slope Game, the male and female protagonists are two sides of the same coin. They both have the same job, but their personalities couldn’t be more different. Kotone Shiomi is clearly bubbly and happy, and she shows how she feels by wearing her heart on her sleeve.
Both Sylveon and Umbreon are from Eevee, but they are very different. But more than that, Sylveon is a cute Pokemon that looks the same as Kotone. It can win and stop fights with its charm and calming aura, but it’s not afraid to fight bigger enemies. It goes well with Kotone’s personality and courage, and the two of them together would be impossible to stop.
Yukari Takeba & Blissey

Yukari seems to be a happy, charismatic girl who is well-liked by her classmates. But if you get to know her, you can see how lonely she is and how she doesn’t trust other people. She is friendly, but at first she doesn’t have anyone she thinks of as a real friend. Blissey shows this by being a nice Pokemon who helps anyone in need but then runs away right away.
Just like Yukari’s Persona, Blissey is good at healing both physical and mental wounds. But it’s hard to even find one, let alone catch it, which shows how hard it is to really connect with Yukari. Chanseys evolve into Blisseys. It is said that Chanseys only evolve if they are very close to their trainers. Because Yukari and Blissey are so much alike, their bond is likely to be strong.
Junpei Iori & Pignite

Junpei is the goofy brother of the group, but he can do and take a lot of damage in battle. His Persona is good at Physical skills, but it also knows how to use Fire skills. Even though he can hit hard and take hits, he isn’t very quick. Pignite is almost exactly the same in every way.
It has the same type as Junpei’s Persona, which is Fire/Fighting. It looks cute, but its highest stats are attack and health, so it can easily beat up opponents. But, like Junpei, it’s the speed that hurts it the most. If Personas were Pokemon, Junpei’s would be Pignite without a doubt.
Akihiko Sanada & Hitmonchan

Akihiko never gives up on a challenge, and when he fails, it only makes him want to try harder next time. He wants to get as strong as he can so he can protect the people he cares about. Hitmonchan is the best partner because he is good at boxing and hits pretty hard in battle.
Just by looking at Hitmonchan, you can tell that it also knows how to use its fists. Its punches are fast and hard, but it gets tired quickly when fighting. In battle, Akihiko is the same. He has a lot of strength but not much endurance. The most important thing they have in common is, of course, the fire that drives them to never give up.
Mitsuru Kirijo & Froslass

Even with everyone possible in the party, Mitsuru is still the most stylish and confident. She is admired and respected, but also feared because she is hard to get close to and punishes people who don’t do what she says. So it makes sense that her Persona learns mostly Ice skills.
Ice/Ghost-type Pokemon Froslass is also scary because it likes to freeze people and Pokemon and keep them as souvenirs. People also say that, like Mitsuru, it punishes men who act badly. Froslass can also use illusions to get other people to do what he wants. This is similar to how Mitsuru uses Marin Karin to charm enemies. Together, they make a very scary pair.
Fuuka Yamagishi & Gardevoir

Fuuka is the leader of the group, so her Persona is all about helping. She is shy and has a soft voice, but she is kind to everyone, even the kids who pick on her. Even though she is shy, she fights very hard to help and protect her friends in battle. She is a lot like Gardevoir in a few ways.
Fuuka’s Persona can figure out Shadows’ weaknesses and skills, and Gardevoir is a Psychic/Fairy type that can see into the future. Fuuka and Gardevoir both do their best to protect their friends, which is when they are at their strongest. Also, the way Gardevoir looks is similar to how Fuuka’s first Persona looked. Neither of them should be taken for less than they are because of how they look.
Aigis & Iron Valiant

Aigis is ahead of her time because she is a robot made by scientists to fight Shadows. She starts out as a typical robot with no feelings, but as the story goes on, she becomes more curious and shows more human emotions. In a similar way, Iron Valiant is a Pokemon that was made by a scientist.
Aigis’s Personas are mostly robots, and most of the skills they learn are physical. Iron Valiant is a Fairy/Fighting-type with physical moves. Aigis has a special move called “Orgia Mode,” in which she lets go of her limits and fights without mercy. Iron Valiant is the same as its enemies, but it is a killing machine that doesn’t care who it kills. If the two were friends, they would definitely talk about where they came from and why.
Koromaru & Houndour

Koromaru is the first and only Persona user who is a full animal. He sticks by his friends and looks out for them. Houndour would be the best Pokemon for him to have as a friend. Not only are they both dogs, but Houndour is a Fire/Dark type and Koromaru mostly learns Fire and Dark spells.
Even though Koromaru doesn’t have his own pack like Houndour, they both have a strong sense of loyalty to those they consider friends. They would never leave a friend behind, which means they would never leave each other.
Ken Amada & Dedenne

Ken, who is only ten years old, is the youngest person in the series to use a Persona. Even so, he seems to be very old for his age. Because he is short, he fights with a long spear to make up for it. Dedenne is pretty small, even compared to other Pokemon, just like Ken.
It is also an Electric/Fairy type, and Ken’s Persona learns Electricity skills. But because it is so small, it doesn’t make a lot of electricity on its own. To make up for this, it takes electricity from other Pokemon or electric outlets. This is like how Ken needs help from other people even though he acts like an adult. If he had Dedenne by his side, she could show him how to be happy about being small instead of being angry about it.
Shinjiro Aragaki & Pangoro

Shinjiro wants people to think of him as a scary, unapproachable loner who will kick your butt if you look at him the wrong way. But Shinjiro is actually a kind, caring person who likes to help his friends and spoil Koromaru. He learns mostly physical skills and is the strongest person in the group, always hitting like a truck.
In the same way, Pangoro looks scary and has a lot of strength, but it is kind to its friends. It looks out for the weak, like Shinjiro does, and always goes into battle with all its strength. They would be both good friends and fierce rivals.