Board Thread:General Discussion/@comment-87.102.2.235-20160720090052/@comment-5430952-20170215123116

He didn't travel with Ruby because he didn't want his Misfortune Semblance affecting her, like it did in the fight against Tyrian. He explained it in V4E8, and it could very well be why Summer died. Either that or he arrived too late to save her, and is leading Ruby towards her "destiny" in hopes of avenging Summer.

As for Yang, he could've very well motivated her to become a Huntress, same as Ruby, against Taiyang and Summer's (final) wishes. So yes, he'll do what he thinks is right, regardless of who says otherwise. Though one day, it could be his undoing.