Ichigo was sent to the Soul Society in order to train to become a captain. For a rule made by Central 46 states that all deputy soul reapers after three years of service must become captains. When The Dark Tower appeared, Ichigo was the first one to investigate it. He was also the first to gain a crest and Kana
Shikai: (Zangetsu "Slaying Moon")Zangetsu absorbs Ichigo's spiritual pressure and releases highly condensed spiritual energy at the tip of the blade, magnifying the slash attack and flies forward. The same goes for his bankai, though it is much quicker and stronger.