inyasha's father.
you know as weird as it sounds, i honestly think that inuyasha's father gave the right swords to his sons. i think since he was a 'great dog demon'. he also understood human emotions. inuyasha has more of his father's qualities in him, and also the face that he is human helps an awful. inuyasha is like a mixture between dog and human, he's loyal and protective (given the right teacher) in kagome's case) and compassionate and loving like human.
i think in a way, he felt as though inuyasha could do more with tetsaiga than sessy could.
I think him meeting Rin was meant to happen, because before he was proud, cocky and a little bit cruel to humans. Until Rin came on the same. Considering that he is also a dog demon, he is fiercely loyal to Rin, just as Inuyasha to Kagome. He just has difficulty showing, and he refuses to greatly.
I think their father wanted them to learn to protect someone, just has he had learned and probably knew how to do, but did more so when he met Inuyasha's Mother.
I LOVE THIS ANIME
The best thing you can do for yourself is be a good spirit