Nee-san!!There wasn't enough light cruisers for this battle plan. So, I'll help out as a Sendai class.No, that's not possible.We have matching ahoges too!You have two sisters...It's fine if she can take part in a night battle.Yay! Naka-chan got a little sister!The reason why Kako, a heavy cruiser, is named after a river rather than a mountain is because of the light cruiser "Kako" which was originally planned as a sister ship of the Sendai-class, but scrapped due to the Washington Naval Treaty. The prevailing theory is that the name was kept because the budget for the original light cruiser was reallocated to the heavy cruiser.
Light cruisers were named after rivers, heavy cruisers were named after mountains