Chas

From the Super Mario Wiki

Chas is a playable character in the game Mario Power Tennis for the Gameboy Advance. He is one of several human characters created exclusively for the Mario Tennis series. He is a speedy-type character and his power shot is the High-Power shot.

Mario Tennis Series Playable Characters
Mario's Tennis
Donkey Kong Jr. · Koopa Troopa · Luigi · Mario · Princess Toadstool · Toad · Yoshi
Mario Tennis (Nintendo 64)
Baby Mario · Birdo · Boo · Bowser · Daisy · Donkey Kong · Donkey Kong Jr. · Luigi · Mario · Paratroopa · Peach · Shy Guy · Toad · Waluigi · Wario · Yoshi
Mario Tennis (Game Boy Color)
Alex · Allie · A. Coz · Baby Mario · Beth · Bob · Bowser · Brian · B. Coz · Curt · Donkey Kong · Elden · Emily · Fay · Harry · Joy · Kate · Luigi · Mario · Mark · Nina · Pam · Peach · Sammi · Sean · Spike · Waluigi · Wario · Yoshi
Mario Power Tennis (Nintendo GameCube)
Boo · Bowser · Bowser Jr. · Daisy · Diddy Kong · Donkey Kong · Fly Guy · Koopa Troopa · Luigi · Mario · Paratroopa · Peach · Petey Piranha · Shy Guy · Waluigi · Wario · Wiggler · Yoshi
Mario Power Tennis (Game Boy Advance)
Barb · Bowser · Chad · Chas · Chris · Donkey Kong · Dweezil · Elroy · Emi · Flit · Gary · Jet · Kyle · Kyoko · Linda · Luigi · Mario · Mason · Max (Clay) · Meg · Mel · Micki · Mynx · Paula · Princess Peach · Roy · Sasha · Sass · Shawn · Sheri · Skipper · Sophia · Sylvia · Tina (Ace) · Tori · Waluigi · Whisker · Willy

Human Characters
Humans in the Mario series A. Coz | Alex | Allie | Azalea | B. Coz | Baby Daisy | Baby Luigi | Baby Mario | Baby Peach | Baby Wario | Bean | Beth | Bird | Bob | Brian | Booster | Buzz | Charlie | Curator | Curt | Elden | Elroy | Emi | Emily | Fay | Flit | Foreman Spike | Gary | Grace | Harry (Mario Golf) | Harry (Mario Tennis) | Helen | Isaac Newton | Joe | Joy | Kate | Ken | Kid | King Fret | Kyoko | Lady Timpani | Lisa | Mama Mario | Mario | Mason | Max | Luigi | Mark | Mushroom King | Napple | Nina | Onnanoko | Oyaji | Pam | Papa | Paula | Pauline | Plum | Prince Pine | Princess Daisy | Princess Peach | Powert | Professor Elvin Gadd | Putts | Rosalina | Rozary | Sasha | Sean | Sherry | Sonny | Spike | Stanley the Bugman | Steve | Thread | Tina | Tori | Waluigi | Wario | Whisker
Humans in the Wario series 5-Volt | 9-Volt | 18-Volt | Ana's Crew | Ashley | Bridget the Baker | Captain Syrup | Carpaccio | Count Cannoli | Dr. Crygor | Dr. Payne | The Dinosaurs | Jimmy P. | Jimmy T. | Kat and Ana | Mona | Mad Scienstein | Penny Crygor | Sal Out | Sammy Rai | Shop Manager Iwata | Young Cricket and Master Mantis
Humans from other series Captain Falcon | Colonel Roy Campbell | Dr. Eggman | Eggman Nega | Ike | Little Mac | Lucas | Marth | Mei Ling | Ness | Otacon | Pokémon Trainer | Roy | Samus Aran | Solid Snake
Humans in other media Captain Falcon | Ali Mustafa | Alligator Dundee | Alyssa Milano | Angelica | Anthony Scapelli | Aunt Luigeena | Aunt Maria | Blanka | Bones | Brian Bonsall | Brutius Maximus Grouchimus | Butterfingers | Captain Abidab | Captain Clump | Captain Lou Albano | Chief Quimby | Cher | Chun-Li | Cowboy Jed | Crab | Crimewave Clyde | Cutter | Cybele | Cyndi Lauper | Daniella | David Horowitz | Dealin' Delbert | Dhalsim | Doc Freud | Dr. Frankenstein | Dr. Light | Dr. Nerdnick | Dr. Sheldon | Dr. Sigmund Fruitcake | Dr. T. Garden | Dr. Toby | Dr. Wily | Edison | Einstein | Elvin Parsley | Elvira | Elvis Presley | Erik, Baleog and Olaf | Ernie Hudson | Fire God | Flab Boys | Friendly Floyd | Gondolier | Gramma Toadstool | Grandma Mario | Grandma Mia | Grandpapa | Ellie Mae | Harry Blackstone Jr. | Helmut Kohl | Hercufleas | Herlock Solmes | Herman | Herman Smirch | Hildy | Imperial Poobah | Indiana Joe | Inspector Gadget | James Blonde | Jason Bateman | Jodie | Joe and Mac | Joliet | Junior | Junior's Parents | Kid Klown | King James | King Mushroomkhamen | King Toadstool | King Windbag | Klösn | Liz | Luigeena | Luigi's Girlfriend | Lyle Alzado | Madam AGoGo | Marco Polo's Plumbers | Marianne | Marilyn | Mario Joe and Luigi Bob | Mark Twang | Max Milliplatt | Mayor of New York City | Mikhail S. Gorbachev | Milli Vanilli | Misaki | Miss Endless | Miss O'Hara | Mervin the Magician | Mighty Plumber | Mona | Mouth of the River | Mr. Gibbel | Mr. Levison | Mr. President | Mrs. Gammliss | Mrs. Periwinkle | Mrs. President | Mugga | Netty | Nicole Eggert | Oogtar | Pam Matteson | Patty | Patty (Saturday Supercade) | Patty's Parents | Pietro | Prince Mushroomkhamen | Prince Pompadour | Queen Mushroomkhamen | Queen Rotunda | Rob Stone | Romano | Romano and Joliet's Fathers | Rowdy Roddy Piper | Roxanne | Salvador Drainado | Sam Shalam | Santa Claus | Secret Agent N | Sergeant Kooperman | Sgt. Slaughter | Shabba-Doo | Submarine Captain | Sultan Pasbah | Susanna Ross | Tawny Tyler | Ted Bull | The Old Psychic Lady with the Evil Eye Who Reads Fortunes and Knows Everything Before it Happens | Tommy Lasagna | Vampa White | Waldo the Wizard | Young McDonald | Zangief | Zero