What was that manga? Does anyone know?

I was talking to my friend about a manga I read a while back and for the life of me I cant remember the name, I hope someone here can help me!

The main character was a young man who was looking for his ageing adopted mom because she disappeared from the family of orphans she had adopted. So he goes out to look for her. It turns out later that she was a martial queen from a well recognized clan and is suffering from dementia which is why she left, and how she wandered in to adopt the orphans in the first place.

On his path he is recognized as a sword genius and by the end he reaches the pinnacle of swordsmanship. I remember the novel being fairly heavy with religious thoughts in the latter half talking about Taoism or Buhdism philosophy or something like that. But the idea is to rech the pinnacle you need to let go of everything else.

Along the way he saves innocents from bad guys and meets masters who are also trying to reach the pinnacle but cant get rid of all earthly attachments. In fact I think the big bad of the manga the "heavenly demon" if you will, is starting a war because he promised his people revenge, but also mainly because he believes that he can reach the pinnacle if he can fight other strong warriors.

There are also musings about how both an evil path and a righteous path can lead to the pinnacle.