I love this headcanon prompt! I always love to think about them with children.
Since he is trying to unify Japan his time is valuable and he doesn’t have much free time, period.
He would spend the day teaching the child a skill I believe. Hunting, fishing, falconry, basically anything outside and something the child will need in life. He is surprisingly patient with children. So even if the child doesn’t get it right away he will start over without complaining and sometimes it will be a few times. He will take pride in passing something useful to the child.
This mother hen will do anything and everything with his kids, as long as he deems it safe enough that is. No hunting or archary for his kids until they are much older. He will teach them as well but more subtle things like manors, leadership, and being a supportive person. He will take them on walks and teach them about the forests along the way. He loves that his kids can name eighteen different types of trees.
He will spend time with his kids by doing more quiet things. Reading books to them is his number ine thing. He shows them the art of medicine and how things can be used. He knows it is a lesson that everyone should know but doesn’t so a skill that is useful. His snarky comments are met with the sarcastic retorts of his children and he enjoys every second of it.
He is the fun dad of the bunch of oda warlords. He will teach them everything he knows. He takes great pride in the fact his kids can go from serious learners to playing a practical joke on someone two minutes later. He will take them to the clearings and have races with them in good weather or bad. He is always doing something with them and he makes time for them as much as possible.
He shares his quiet and gentle nature with his kids. They don’t have to do much for them all to be relaxed and reading together. Mitsunari loves to expand their horizons and loves teaching them joys of math.(None of them find Math enjoyable) He will do whatever they want and his kids are masters with a sword, like him by the time they are ten.
He often has zero free time. His lord has to many enemies for him to have that much. However his growing family is more important to him then his job most of the time. He will spend the day walking around with his kids showing them the world. He has very few rules and the kids love that. He will buy them treats at the shops and they will sit and talk for hours devouring them. What he teaches them is reality and how things work. Honest conversations between all of them leaves the family tight knit even when he is gone.
He will show them the lake. They know not to go into it but they like looking at the koi that are there. Kenshin dotes in his children but also teaches them like he does his ninjas. All of the children, even his daughters, are skilled with weapons and as their uncle Sasuke says the ninja arts. He can be found with one or more tucked into his side as he makes up stories about a fierce dragon at war.
These kids love their father. They will play on him, around him, and over him. He is calm and kind as he teaches them how to do nearly everything. They know what seasons to plant what crops, they know how to fight, they know how to flirt, but most of all they know they can do anything and their father will be proud of them. He shows them the world as he stands back and watches.
Like Masamune he is the fun dad. He is also the hard working dad. He doesn’t get alot of time between babysitting Shingen and busting the troops. He will take the kids somewhere to be outside telling them stories of things from when he was a boy and shingenteaching him things. He will get into a tickle fight and then teach the kids some life saving things.
This one will be that dad. The dad that shows up out of thin air and then disappear again. His ninja skills are passed down to the kids and he delights in their love of ground spikes as well. He constantly talks about things from the future and how they can change things here and now. He teaches them everything and is gentle with them as he reads intro to physics to them every night.