Here are the audience that'll be reacting
-High School DxD

Backstory: In this universe: Kevin is a twin brother of Issei Hyoudou and childhood friend of Akeno Himejima. He discovered Issei has been abusing and raping Rias and her Peerage ever since they started dating and rescued them from his wrath. Seeing Kevin has a righteous heart and true potential, Ddraig has chosen Kevin as his new host. Kevin becomes the true Red Dragon Emperor and every girl in ORC and Kuoh now wants him for themselves.

Characters: Rias Gremory, Akeno Himejima, Koneko Toujou, Yuuto Kiba, Isami Hyoudou, Asia Argento, Xenovia Quartz, Irina Shidou, Gasper Vladi, Rossweisse, Sona Sitri, Tsubaki Shinra, Ravel Phenex, Yasaka, Kunou, Azazel, Sirzechs Gremory, Serafall Leviathan, Zeoticus Gremory, Venelana Gremory, Millicas Gremory, Vali Lucifer and Kuroka Toujou.

Harem: Akeno Himejima, Rias Gremory, Koneko Toujou, Isami Hyoudou, Asia Argento, Xenovia Quartz, Irina Shidou, Rossweisse, Sona Sitri, Yasaka, Serafall Levitation and Kuroka Toujou.

Pairings
-Kiba x Tsubaki
-Kunou x Gasper x Ravel

-My Hero Academia

Backstory: In this universe: Kevin is childhood friends with Izuku Midoriya and twin brother of Katsuki Bakugo. Unlike Bakugo, he's far more chill and kind to his friends. He also has a way better Quirk than his brother and he got into Class 1-B and befriended the entire classmates...except for Monona of course.

Characters: All of Class 1-A and Class 1-B, Hitoshi Shinso, Mei Hatsume, Miro Togata, Nejire Hado, Tamaki Amajiki, Shota Aizawa, Vlad King, All Might, Present Mic, Thirteen, Cementoss, Midnight, Mt. Lady, Power Loader, Nezu, Recovery Girl, Eri, Kota Izumi, Ms. Joke, Endeavor, Hawks, Best Jeans, Mirko, Ryukyu, Gang Orca, Kamui Woods, Mandalay, Pixie-Bob, Ragdoll, Tiger, Gran Torino, Fat Gum and Death Arms.

Harem: Momo Yaoyorozu, Tsuyu Asui, Kyoka Jiro, Mina Ashido, Toru Hagakure, Itsuki Kendo, Yui Kodai, Kinoko Komori, Ibara Shiozaki, Pony Tsunotori, Setsuna Tokage, Reiko Yanagi, Mei Hatsume, Nejire Hado, Midnight, Mt. Lady, Mirko, Ryukyu, Mandalay, Pixie-Bob and Ragdoll.

Pairings
-Izuku x Ochaco
-Aizawa x Ms. Joke

-RWBY

Backstory: In this universe: Kevin is a Wolf Faunus, the rarest and only last species on Remnant. He was found hurt and starved by Team RWBY after defeating a bunch of Grimms at Mountain Glenn and Ozpin placed him in Team RWBY's team. He got along with many people at Beacon and what he didn't know is that every single girl wants him for themselves.

Characters: Team RWBY, Team JNPR, Ozpin, Glynda Goodwitch, Team CFVY, Sun Wukong, Neptune Vasilias, Penny Polendina, Oscar Pine, Winter Schnee, Willow Schnee, General Ironwood, Ace-Ops, Peter Port, Bartholomew Oobleck, Arslan Altan, Qrow Branwen, Taiyang Xiao-Long, Summer Rose, Raven Branwen, Ghira Belladonna, Kali Belladonna, Ilia Amitola and Salem's Faction.

Harem: Team RWBY, Team JNPR, Glynda Goodwitch, Coco Adel, Velvet Scarlatina, Penny Polendina, Winter Schnee, Willow Schnee, Harriet Bree, Elm Ederne, Arslan Altan, Summer Rose, Raven Branwen, Ilia Amitola, Cinder Fall, Emerald Sustrai, Neopolitan and Salem.

-Senran Kagura

Backstory: In this universe: Kevin is the only boy in Shinobi Academy and doesn't peek on girls like those boys. Bitten by a radioactive spider, he has the ability to climb on walls, sense danger around him, and spin strong webbing with his web shooters. Naming himself Ninja Spider, Kevin protected Shinobi Village as a vigilante.

Characters: Team Hanzo, Crimson Squad, Team Gessen, Team Hebijo, Kiriya, Daidōji, Suzune, New Hanzo, New Hebijo, Milky Pop, ARC Angels, Team Shogei, Team Shinozuka, Team Maisen, Team Hakuoh, Tengu Squad, Team Zodiac, Kagura Festival Girls, Independent, Senki Shu and Bandits.

Harem: All of Senran Kagura Girls.

-The Owl House

Backstory: In this universe: Kevin is Luz's childhood friend from middle school and always sticks with her to the end including helping her archive her dream of becoming a witch. He knows how to use all kinds of magic than anyone. He has a crush on both Luz and Amity.

Characters: Luz Noceda, Eda Clawthorne, King, Willow Park, Gus Porter, Amity Blight, Hunter, Boscha, Edric Blight, Emira Blight, Viney, Jerbo, Barcus, Skara, Lilith Clawthorne, Perry Porter, Odalia Blight, Camila Noceda and Vee.

Harem: Luz Noceda, Eda Clawthorne, Amity Blight, Emira Blight, Viney, Lilith Clawthorne, Odalia Blight, Camila Noceda and Vee.

Pairings
-Willow x Hunter

-Amphibia

Backstory: In this universe: Kevin is an only male friend of The Calamity Trio. Along with the trio, he got transported into Amphibia as well but at the cost of him falling and hitting his head, resulting him to lose his memories forgetting everything about his old life. He was alone for somehow weeks until the trio found him after they left Newtopia. The trio were sad that their friend/crush had lost his memories about what they used to do but they will do anything to help Kevin remember. His favorite is yellow because he likes it when Goku transforms into a Super Saiyan and he finds it awesome.

Characters: Anne Boonchuy, Sasha Waybright, Marcy Wu, Sprig Plantar, Polly Plantar, Hop Pop Plantar, Frobo, Major Toadstool, Toadie, Wally Ribbiton, Maddie Flour, Felicia Sundew, Ivy Sundew, General Yunnan, Lady Olivia, Joe Sparrow and Mr. and Mrs. Boonchuy.

Harem: The Calamity Trio, Maddie Flour, Felicia Sundew, General Yunnan and Lady Olivia.

-Steven Universe

Backstory: In this universe: Kevin meets Steven while fighting against a monster who was tasked to kill the Crystal Gems. Like Steven, Kevin is also a Crystal Gem and mastered his powers in over a year. Now he fights alongside Steven and his friends against all kinds of threats. Is in a relationship with Spinel.

Characters: Steven Universe, Garnet, Amethyst, Pearl, Connie Maheswaran, Peridot, Lapis Lazuli, Jasper, Bismuth, Greg Universe, Lion, Yellow Diamond, Blue Diamond, White Diamond, Yellow Pearl, Blue Pearl, Spinel, Rutile Twins, Rhodonite, Padparadcha, Fluorite, Lars Barriga and Sadie Miller.

Harem: Spinel, Garnet, Amethyst, Pearl, Peridot, Lapis Lazuli and Jasper.

-The Loud House

Backstory: In this universe: Kevin was adopted by the Loud family and becomes like a big brother to Lincoln Loud whenever things get tough for him to go through in the past. He is the same age as Lori but not as bossy as her and loves to hang around with his family and friends. Little did he know is he's a chick magnet.

Characters: Lincoln Loud, Clyde McBride, Lori Loud, Leni Loud, Luna Loud, Luan Loud, Lynn Loud, Lucy Loud, Lana Loud, Lola Loud, Lisa Loud, Lily Loud, Rita Loud, Ronnie Anne Santiago, Sid Chang, Bobby Santiago, Maria Santiago, Carlota Casagrande, Carl Casagrande, Carlos Casagrande, Stella Zhau, Sam Sharp and Haiku.

Harem: Leni Loud, Luna Loud, Luan Loud, Lynn Loud, Lucy Loud, Lana Loud, Lola Loud, Lisa Loud, Rita Loud, Maria Santiago, Carlota Casagrande and Sam Sharp.

Pairings
-Ronnie Anne x Lincoln x Sid Chang
-Clyde x Haiku
-Lori x Bobby

-My Little Pony: Equestria Girls

Backstory: In this universe: Kevin is best friends with the Humane Six and currently Sunset Shimmer's boyfriend after the Battle of the Bands. He is known for his kindness and willingness to do anything for his friends.

Characters: Twilight Sparkle, Rainbow Dash, Pinkie Pie, Rarity, Applejack, Fluttershy, Sunset Shimmer, Sci-Twi, Spike, Cutie Mark Crusaders, Celestia, Luna, Cadence, The Dazzlings, Shadow Five, Trixie Lulamoon, Starlight Glimmer, Juniper Montage and Wallflower Blush.

Harem: Sunset Shimmer, Twilight Sparkle, Rainbow Dash, Pinkie Pie, Rarity, Applejack, Fluttershy, Sci-Twi, Celestia, Luna, Cadence, The Dazzlings, Shadow Five, Trixie Lulamoon, Starlight Glimmer, Juniper Montage and Wallflower Blush.

(A/N: I'll add more whenever I feel like updating another one. For now, stay tuned for the first reaction.)