During story or stage select:
Stage 5 -
Aku City This is obtained at the end of the level. Will take you around 20-30 mins to make your way towards the end.
Important note:
Make sure you have samauri fist equip. Also to be safe play on Samurai difficulty.There are two bounty hunter bosses you'll fight them throughout the train room. One is Ezekiel Clench looks like a outlaw clown and Josephine Clench lady outlaw. Once you see Joshphine glow pink it will be time to throw her and the last fight. I K.O.ed Ezekiel and focused on him first. I tried to bait him so Josephine wouldn't attack me. I couldn't throw him.
After you K.O. him, get Josephine kind of weak then she'll sit on the ground this is where you want to equip samurai fist and use
to use her parasol and throw her to space. (Smash Bros Easter egg)
Also can unlock on:
Stage 3 -
Cave of the Ancients To be safe play on
Samurai difficulty.
Beat Ancient King boss. Have to make sure he is in the down position equip samurai fist and then RB to throw him when his health is low. Unlocks a Mace.
Doing these can unlock different weapons. This goes towards Armed to the teeth and collecting all weapons in the game.