Kodachi is what you might call a muscle brained and honest fool. She believes in one truth and one person and nothing else.
Yume is the person; and the truth is Atk is the only form of def that exists in a fight. So her decks contain weapons and those that wield them and going second is her only choice. Turn without a battle phase is a waste of time.
This deck is the version she starts with in my story. Harpy Girl and Souls of the forgotten are some of my signature cards with my characters if they have a purpose at all. Amulet of Ambitions turns my Lv 2 normys into dangerous threats against high level synchros or main deck monsters.
Benny is her ultimate atker as he gets one per equip on him his norm and a "second" with Twin swords meaning he can overcome a lot. one megamorph on a chainsaw is enough to overcome most threats.
remember with this deck attacking really is your only chance at preventing future threats so never hesitate.