Disclaimer: I do not own Katekyo Hitman Reborn!
Summary: He viewed the world differently, because along the five traditional senses of sight, hearing, taste, smell and touch – he has been gifted with a special sense for warmth. / about Tsuna's childhood, AU, sensor!Tsuna
Tsuna was always warm.
He may not have anyone to compare his experience with, but Tsu-kun knows that he has always felt warm. A very cuddly warm feeling that made him feel safe.
Kaa-chan is also warm, but different from Tsu-kun.
Kaa-chan's warm feeling is really soft and smaller than Tsu-kun's. But it doesn't make her colder, because she shines all the more brightly towards the outside. Sometimes Tsu-kun tries to grab the 'outside-shining', but Tsu-kun has never succeeded, not even once. Still, Tsu-kun will continue to try, he won't give up.
Kaa-chan is really amazing. She is the first person who showed Tsu-kun that the warm feeling can be used actively. Sometimes, Kaa-chan makes these pretty flowers around her, mostly when she is really happy.
Tsu-kun's warm feeling stays in Tsu-kun like water in a cup, it doesn't do much. He has to admit that he finds it a bit boring, but Tsu-kun is glad he always has his warm feeling. He really can't imagine a Tsu-kun without it.
Sometimes, Tsu-kun also feels a very strong warm feeling (later he learns it can be called 'heat').
It was so warm, Tsu-kun would have sweated if he could have felt it like the normal warmth, like when he is playing under the sunshine, especially in summer. No, Tsu-kun wasn't afraid of the strong warm feeling. Even if such heat sometimes reminds him of the oven in Kaa-chan and Tsu-kun's kitchen.
Although Tsu-kun has been banned from it for a while now, because one time he touched the oven while it was baking some cookies, and the oven slightly burned Tsu-kun's hand. It had really hurt, but Tsu-kun knows the oven didn't mean to, so Tsu-kun can forgive the oven. Nonetheless, now it's only Kaa-chan's oven.
Tsu-kun doesn't always get near enough for him to be able to touch the man who is heat. Tsu-kun doesn't know who the heat-man is, but Tsu-kun remembers dirty blond hair, like the sand on the playground. He also remembers the funny feeling in his stomach when heat-man gave him a piggyback ride. Heat-man really loves those, because he always gives one to Tsu-kun when he visits and stays long enough to play with him. Tsu-kun can tolerate that.
What Tsu-kun can't tolerate and really dislikes is the horrible smell. Sometimes, heat-man drinks from some bottles that also smells horrible. And then he sleeps on the floor, sprawled out like he's ready to make some snow angels. Tsu-kun wonders if heat-man tries to do the thing that Kaa-chan does. Only Kaa-chan does it really well, because afterwards she smells like flowers. She told Tsu-kun once that she puts the flower water on herself to smell like that. Tsu-kun can't remember the name of the flower water, only that it starts with 'p'.
Tsu-kun doesn't know if he likes going outside. There are lots of interesting things. However, there were a few times when Tsu-kun just felt really overwhelmed.
(Later, Tsuna theorizes that he had been exceptionally flame sensitive, because his very young self hadn't learnt yet how to effectively filter all the information that his special sense provided him with.)
Very early on, Tsu-kun doesn't remember when, he had been able to sense a warm feeling even from trees. Thankfully, it only extended to the many-years-old trees. Therefore, he hadn't regarded other plants like grass, flowers, bushes and even saplings the same as those warm trees in the past. Because the former never possessed the warm feeling that the many-years-old trees had. Just like Kaa-chan and Tsu-kun had. So those plants would be more similar to stones, right?
Or maybe their warm feelings were just so tiny that Tsu-kun couldn't sense them.
But Tsu-kun tried not to think about that, because it would make him feel guilty for thinking the trees were better plants than the others such as flowers, when they were in fact not any poorer in warmth. It would be like saying Kaa-chan isn't the same as Tsu-kun, just because Kaa-chan's warm feeling was colder. Thinking that, Tsu-kun had understood that the other plants would be upset.
Tsu-kun had always wondered why saplings didn't have the same warm feeling as trees. Kaa-chan told him that saplings are the children of trees. Saplings grow into trees someday. Therefore, shouldn't the saplings also have a warm feeling, just like the older trees and Tsu-kun? He had always been told that children grow stronger, so they can become adults in the future. Tsu-kun didn't understand why the warm feeling would need to grow in trees, because Tsu-kun was already completely filled with his warm feeling. Tsu-kun thought he was right. Didn't it make sense that especially the children would have that warm feeling to protect them?
Tsu-kun definitely (almost) always feels safe. As a matter of fact, when Kaa-chan wanted Tsu-kun to sleep in his own room – alone, in the dark – he managed to stay (long enough) in his room (to fall asleep). Tsu-kun wouldn't have been able to do that without his warm feeling. It comforted Tsu-kun enough for him to keep being brave.
(Although the next morning Tsu-kun still cried to Kaa-chan, unable to keep the feeling of being scared from last night inside him. But Kaa-chan said she was still proud of Tsu-kun for enduring it so long.)
The topic revolving around the plants slowly faded from Tsu-kun's mind along with the ability to feel the trees.
Instead, animals have come to his attention. The warm feeling Tsu-kun gets from them is different than the warm feeling he got from the trees. As young as he has been then, Tsu-kun has only felt the warm feeling of trees as something really foggy. Tsu-kun has to concentrate if he wants to feel one tree at a time. Most of the time they are like mist, drifting about in the background and not bothering Tsu-kun when he has gotten used to the feeling. Especially near parks and forests, because there are lots of them standing together very closely.
Animals feel small. They feel more solid, but their warm feelings are a lot smaller than Kaa-chan's.
Older Tsuna would rectify his younger self who hadn't seen any animals bigger than the average dog yet. It varies with their sizes, but it stands that their warm feeling is always smaller than the humans.
It might be because humans are capable of more complex emotions and are able to regret more, which is an important key to the Dying Will Flames. The complexity which animals lack is the possibility of feeling emotions outside of a life-and-death situation, but experiencing them just as intensely as the desperation felt in a life-threatening situation.
Only the box weapons are an exception, they are in a whole different league above normal animals.
Tsu-kun has a right to feel afraid of chihuahuas. They have really sharp teeth and they bark really loudly. Tsu-kun doesn't see any good in them. Besides, their warm feeling is so small, it doesn't comfort Tsu-kun at all. That's why he likes to hide himself in Kaa-chan's hugs. They are comforting, warm and make him feel the best feeling ever. Not because Kaa-chan can also protect Tsu-kun from the chihuahua then.
A/N:
Anyone interested in how sensor Tsuna would react to people he meets later on?
If yes, should Tsuna stay little – which could make it more AU, like meeting Varia early, and so on – or should Tsuna grow older?
Please review.