It's been over 50 years. He looks... different.
He'd seen him before, when he was alone. The amber eyes were hard; his claws sharp and always at the ready, and the passage of his life was marked by fight after fight after fight. His manner was rude, his language foul, and everything about him screamed don't fuck with me.
Then he fell in love with the great priestess Kikyou. He noticed that the hanyou never did try to kill her; his eyes softened slightly in her presence, and they called each other by name.
Tragedy struck. The miko died, and the hanyou slept for 50 years on a tree as great, perhaps greater, than the girl had been.
He'd visited him there, on the tree. He'd peered at the features relaxed, finally, in supposedly eternal slumber; gotten an up- close look at the lethal claws; rubbed the fire- rat armor between his fingers; couldn't resist stroking one silky- smooth dog ear.
The hanyou didn't look so different sealed on the Goshinboku.
But it was when he was unsealed, after he'd been travelling with the girl Kagome, the orphaned kitsune Shippo, the cursed houshi Miroku, and the taijiya Sango who was partnered with the firecat mononoke Kirara that the hanyou's face changed. He was still rude, to be sure; still quick to anger (though not quite so quick to confrontation anymore), still as foul- mouthed as it was possible to be; but he had changed.
The eyes were most striking. They were no longer the wary, guarded eyes of a hunted animal. These were human eyes colored amber with a vertical pupil.
The fangs were no longer the main focal point of his smile.
His entire face, in fact, had softened. His shoulders were no longer constantly tensed; his body no longer seemed to thrum with ready, nervous energy around everyone but his beloved.
His guard was down and he was at the top of his game.
Instead of lessening the appeal, this made it more interesting. What a change! How interesting, to see them interact with one another! How interesting, to work out what roles they played in the group, to try to predict what they would do, to watch the strange fusion of such diverse forces working together. How interesting, to see the changes they wrought in one another, to watch the hanyou fall in love all over again, to watch him become friends with a human male for the first time, to observe his relationship with the kit which was (judging from his interactions with the powerful youkai Sesshoumaru) brotherly. How interesting, to watch him play a more traditionally protective brotherly role with the strong taijiya.
For over 50 years he'd watched this hanyou, and he hadn't been bored yet.