Board Thread:General Discussion/@comment-26475399-20150621155415/@comment-25687181-20150825021625

Yes, but Ichigo is actually much stronger. The fact is, during Aizen's chrysalis period, Isshin couldn't sense Aizen's spiritual pressure. Ichigo could. Aizen said that he had arisen to a level where people couldn't sense his spiritual pressure unless he purposely brought his spiritual pressure down to a level they could sense. So if Ichigo was able to sense Aizen's power when Isshin couldn't, it means that Ichigo was actually stronger than Isshin. So this disproves your theory that Isshin is a child of the Soul King, because Ichigo is his son, and therefore should be weaker than him, if even slightly. Plus, in the "Everything But The Rain" chapters, Isshin is shown to be a part of the Shiba family.