Maybe there is a group of characters where one stands out as the most important in relation to the'sister' concept. They might have distinct personalities, like one being very kind and nurturing, while another could be more rebellious but still deeply connected to the idea of sisterhood within the context of the fanfic.
I'm not sure specifically as I haven't read it in detail, but it's likely that there are characters who are sisters, and perhaps other family members or friends who interact with them.
I'm not entirely sure without reading it in detail, but likely the sister is one of the main characters. And there's probably a male protagonist who has a special relationship with the sister.
I'm not sure specifically as I haven't read it. But it could be the main characters from the original work on which the fanfic is based. For example, if it's a fanfic of a TV show about a group of friends, the main characters would likely be those friends, and the fanfic would explore their love relationships in new ways.
The novels have complex character relationships and engaging storylines. The focus on family bonds and the inner world of the characters is quite remarkable.
There's no way to accurately determine who the main characters are without reading the 'love is all you need 2016 fanfiction'. They could be a young couple trying to find their way in a world full of challenges in 2016. Or perhaps it could be a group of friends where one of them is searching for true love during that year. It could also be a story about a family and how their love for each other endures in 2016.
In the 'All You Need Is Kill' novel, the main character is Keiji Kiriya. He's a complex character who starts as a relatively inexperienced soldier but gradually becomes a battle - hardened and strategic thinker due to his repeated experiences in the time loop. There are also other supporting characters like Rita Vrataski who play important roles in the story's development.
I'm not sure as I haven't read the novel specifically. But typically, in a novel with such a title, there might be a protagonist who is searching for love or learning about its true meaning. There could also be a love interest, and perhaps some supporting characters like friends or family members who influence the main character's journey regarding love.
Without having read the 'love is all you need novel', it's difficult to name the specific main characters. But in a novel with such a title, we might expect to find a central character who is perhaps cynical about love at the start. Then there could be another character who comes into their life and changes their perspective on love. There might also be side characters like a wise old person who gives advice on love or a group of friends who support the main character's exploration of love.
In addition to Ciel and his sister, there could be new characters created specifically for the fanfic. These new characters might be friends or foes of the sister. For example, a mysterious traveler who befriends the sister and helps her in her adventures, or a villain who is after something that the sister possesses.
In this fanfic, there might be a lot of emotional moments. The relationships between the characters, especially those related to the concept of sisterhood, could be delved into deeply. There could be moments of joy, sadness, and growth for the characters, which make the fanfic engaging and relatable to readers.