I think Angel from Buffy the Vampire Slayer also shows up a lot in these fanfictions and is popular. His tortured soul and his own history of fighting vampires, along with his relationship with Buffy, add a lot of depth to the stories. And of course, there are always the new and original characters that some fanfiction authors create to add their own unique twists to the Buffy - meets - Blade concept.
In many Buffy meets Blade fanfiction stories, Whistler from the Buffyverse is quite popular. He has a lot of knowledge about the supernatural world and can act as a sort of guide or informant for Buffy and Blade. Also, Dr. Karen Jenson from the Blade movies might be included and be popular. She can bring her scientific knowledge to the mix, especially when it comes to understanding the new vampire threats or creating new weapons to fight them.
Harry Potter himself is often a popular character in these crossovers. His connection to magic and his hero status in his own world make him an interesting figure to pair with Buffy. He can bring his knowledge of spells and the wizarding world to the mix.
Buffy herself is quite popular. Fans like to see how she'd interact with the Twilight characters. Edward also often features prominently as his brooding nature contrasts with Buffy's more action - oriented personality. Another popular character is Spike from Buffy. His edgy vampire persona can create interesting dynamics when paired with the Twilight vampires.
Faith, another slayer in the Buffyverse, could be a popular character in these crossovers. Her more rebellious nature compared to Buffy could lead to some interesting storylines when combined with the Highlander's world. And from the Highlander side, Connor MacLeod could be a great addition. His own experiences with immortality and his fighting skills would mesh well with the Buffy characters.
Definitely Buffy. She's the one who the whole story revolves around. Her courage and determination make her a fan favorite. Angel is another popular character. He's a vampire with a soul, and his relationship with Buffy is full of drama and emotion. Xander is also popular among readers. He may not have special powers like Buffy or Willow, but his loyalty and humor are endearing.
Starscream is another one. He's known for his ambition and treachery in both universes. In 'tfp meets tfa fanfiction', seeing how the two Starscreams interact - whether they team up against their respective Megatrons or try to outdo each other - can be really engaging for fans.
Chara is often a popular character. Their complex nature makes them interesting to explore in the context of Storyshift. They can be portrayed in different ways, sometimes more sympathetic than in the original Undertale.
The most popular characters in 'Boruto meets Naruto fanfiction' are Naruto and Boruto, as they are the main focus of the concept. However, characters like Jiraiya can also be very popular. His connection to Naruto and his own legendary status add depth to the fanfiction. Shikamaru is another character that fans like to see in these stories. His intelligence and laid - back attitude can create some interesting interactions with the main characters.
Agumon and Pikachu are often popular. They are the iconic starters in their respective series. Fans like to imagine their interactions, like if they would compete or play together. Since they both have cute and friendly appearances, it's easy to picture them as friends in fanfiction.
Twilight Sparkle from MLP is often a popular choice. Her intelligence and powerful magic make her a great character to interact with the complex world of Undertale. In Undertale characters, Sans is also quite popular in these crossovers. His laid - back but mysterious nature can create interesting dynamics when paired with the ponies.
Batman and Wolverine are really popular. Batman's detective skills and gadgets combined with Wolverine's berserker rage and healing factor create a lot of interesting story possibilities. They can both be very dark characters at times, and their team - up or clash in fanfiction always attracts readers.