Alfred Pennyworth is a must - include character. He could provide insights into Bruce Wayne's state of mind during this crucial year. His loyalty and wisdom could also be a guiding force for Bruce as he navigates his new role.
The Penguin could be a great addition. His wacky and devious schemes always make for an interesting story. Also, Catwoman. Her complex relationship with Batman adds a layer of intrigue. And Oracle, who can provide valuable information and support from afar.
Deathstroke is always a formidable foe. He has a history with both Batman and Nightwing. His skills as a mercenary and assassin could lead to some intense battles and strategic cat - and - mouse games in the fanfiction.
Alfred Pennyworth could be included. He could offer his wisdom and support to both heroes. Maybe he even has some insights about the similarities and differences between Gotham and Starling City. Another character could be Felicity Smoak. She could help with the tech - related aspects of the case they are working on together.
The Joker would be an interesting addition. He could play on the divide between Batman and Robin, maybe by tricking Robin into thinking Batman has gone too far. Another character could be Catwoman. She could be a mediator or perhaps add more chaos to the situation. Oracle, too. She might try to help them resolve their differences or her information could be misinterpreted and fuel the conflict.
Alfred should be included. He can provide Batman with support and advice, and his unique perspective on things could add an interesting element when Supergirl is around. He might even offer her some tea and wise words.
Alfred is a great character to include. He provides wisdom and a sense of family to both Batman and Robin. His insights can add depth to the story.
Joker is a must - include. His chaotic nature would add a lot of drama to any crossover. He could be causing mayhem that draws in characters from other universes or teams. Another one is Catwoman. Her ambiguous relationship with Batman can create interesting dynamics, especially when other characters are involved.
Alfred would be a great addition. He could offer his wisdom and support to Batman and Batgirl's relationship, and also provide some much - needed comic relief. Another good character is Commissioner Gordon. His connection to the Bat - family and the police force could add an interesting dynamic to the story, especially if he has to deal with the relationship between Batman and Batgirl in some way.
Obviously, Batman himself, Bruce Wayne. Commissioner Gordon is also very important as he is one of the few honest cops in Gotham. And Selina Kyle, who is Catwoman, also plays a role.
In 'Batman Beyond Crossover Fanfiction', Terry McGinnis is a must - have. He is the main protagonist. Another popular character to include is Max, Terry's friend. She can provide support and a different perspective. Also, characters from other DC Animated Universes like Static Shock could be included. His electrical powers and street - smart attitude would contrast well with Batman Beyond's high - tech and more serious approach.