In a way, both connected through their circumstances. Of course, Kaname couldn't fully relate to Kagami's problems, but the other way around, Kagami couldn't also relate to Kaname's. Still, they found a confidant in each other, a person who tried to understand... and definitely a person who reached out.
Kaname knew Kagami before he got to know her, she often saw him following Tobirama around as he helped him with tasks or was even invited to the big garden behind the Senju estate to train. She was able to see his growth in the way he mastered his abilities, even though she thought it was awfully weird that Tobirama was intent on training a boy that wasn't even in academy age.
One evening at dinner, Kaname curiously asked Tobirama about the curly haired boy that he often brings to their estate and Tobirama answered. "Uchiha Kagami. He may not look like it, but he is now 7 years old. I have decided to train him a little more personally, as he has a strong affinity to water." Of course at first she was appalled at her uncle taking an Uchiha under his wing, but it also tickled the curiosity as to *why*.
And the why would be answered another evening, in which Tobirama had invited Kagami to stay for dinner and he would bring him home after and there he was: Scrawny, a bit dirty, his clothes definitely too big on his little body. But he had those huge, onyx eyes and a shy, caring smile. Kagami was polite and gentle in the way he talked and it tugged at something in Kaname's heart.. because in the way she saw some kind of loneliness in the other child, that she herself was also starting to feel.
They befriended each other quickly.. And Kagami never was one to flaunt his abilities, nor was he ever someone to poke fun at her for her lack thereof. He often came to her with genuine interest of doing something together, often it ended with them taking care of the Uchiha strays, because that was something that brought them together: the love for cats. Kaname one day witnessed the way his guardian Mimiko talked to him, the way he flinched away from the woman's touch and while she wasn't able to understand it fully, she knew immediately that whatever happened... shouldn't be happening.
Kaname eventually learned what all these signs meant.. And while he always appeared with the sunniest smile, she made sure that she treasured his safety with utmost care (Just like he did for her).
Their solid bond never changed, it grew closer with each day that passed. Admittedly, he was a little heartbroken when he watched her fall in love with the Hyuuga boy.. Although he couldn't deny that he was happy for her - He seemed to treat her well, even when that relationship was quite a secretive one. The big fallout of it was never something he dug into.. But he was there, or at least he tried his best. He offered the tightest and maybe most secure hooks when tears overwhelmed her and he definitely agreed when she complained about Hiruzen's pushiness. He wasn't in the village when this finally exploded, but he was one of those that came quickly to hear her side of the story and one of those who was also appalled on her behalf. (She would probably never know that Kagami approached Hiruzen for this... She probably won't ever know that it got to a fight... And she wouldn't even know that Danzo had to pry him away when his Sharingan swirled to life in that moment...)
Despite everything, Kagami was happy that his presence never grew to be an unwanted one in her life, he felt that sweet sting on his chest when she greeted him back after long missions. And there was something incredibly warm about the way she fussed and worried when he came back injured. Still it took some time for them to discover what had been right in front of them all this time: each other.
It was right after one of the spring festivals, they both decided they rather wanted to watch the fireworks from a place they would be without people. And while the colorful little bombs lit up the sky, Kagami finally made his confession to her, which to her was rather unbelievable at first. What would such a skilled shinobi, a personal ANBU of Tobirama want with someone like her? What would she even be able to offer him at all? Kagami had a lot of answers to these questions:
"Nothing could ever compare to how I see you, Kaname. And I know you struggle to see all the good, but when I look at you.. I finally understand what is good about a world that is so full of gruelling things. I look at you and all I see is the warmth and love you've given me already. I look at you and I always feel like I am about to cry, because I count myself as the luckiest person alive.. that you chose to let me into your life.... My heart sees you.. and it has been singing your name for quite some years."
It was impactful.. And while she still was hesitant because of her past experiences, Kagami had always been genuine and good to her.. And she was able to let herself feel.. Able to let herself embrace the same love she was feeling for him. Kagami prove to be someone who fought for her, even when the Uchiha voiced the dislike of their union, Kagami was the one to give them the proverbal middlefinger. Even going as far as telling them, that he would gladly lay off the Uchiha name, to show everyone that she would be the wife that he would forever hold in his arms -- with the Senju crest proudly on his back.
Danma and Kagami's relationship has always been a little peculiar. As Kaname's older brother, he was always rather protective of her and after the heartbreak she had went through, he was especially wary of anyone professing their love to her. And now, even worse, it was an Uchiha... Another one of those with special eyes. Their interaction often slipped into banter fast, no one around them ever was fully sure just how serious it was when they hurled insults at each other.
Never below the belt, of course. But just the usual:
"Curly dwarf." - interactions.
The moment when Danma grew more and more scepsis towards Kagami, his jabs became more pointed - he wanted Kagami to know where he stood and that he would break every bone in his body if he ever made Kaname cry.. Something that Kagami took quite seriously. Kaname was worried that they now would brawl, absolutely ruining each others faces with fists, but what followed was a serious exchange between men, one in which Kagami fonally cleared up why he would never hurt Kaname. One in which Danma's somewhat hostile stance eased up... and he started to accept.
It was crucial, because after that, they finally were able to become friends. They still banter with each other, but now on a friendly-teasing tone.
(I am sorry here.. I have no clue about Headcanons with Kichiro Q_Q But he probably loves him like a little brother and allows him to ride his shoulders haha!"