From Kanpachi:
Aegislash Blade Forme stats. I think you will be pleased:
http://i.imgur.com/Gbekyz1.jpg
Aegislash starts the battle in Shield Forme. It seems he changes to Blade Forme when you use an attack that deals damage, and back to Blade Forme when you use something like King's Shield. Here's what I've observed:
Battle start, Aegislash in Shield Forme.
I select King's Shield.
Aegislash uses King's Shield, stays in Shield Forme.
Enemy attacks. The damage is prevented, and the enemy's Attack harshly falls.
Turn two, Aegislash in Shield Forme.
I select Iron Head.
Enemy attacks, Aegislash takes damage normally.
Aegislash turns to Blade Forme and uses Iron Head.
Turn three, Aegislash in Blade Forme.
I select Swords Dance.
Enemy attacks, Aegislash takes damage normally.
Aegislash stays in Blade Forme and uses Swords Dance.
Turn four, Aegislash in Blade Forme.
I select King's Shield.
Aegislash turns to Shield Forme, uses King's Shield.
Enemy attacks. The damage is prevented, and the enemy's Attack harshly falls.