Heikinteki Josei is the first boss encountered in this game. She can be found on level 5. She is a girl carrying a pink lunchbox with a cartoon Genbu on it.
The next boss appears at level 15, called Genbu. It also appears in one of the 'assist ally' minigames. If a player wins, he/she obtains a relic, called Genbu's Scale (+8% attack speed, +10% critical), gold and experience, and an achievement worth 10 Karma. Also, if the player defeats it using only food items (Fried Shrimp, Negi, Stinky Fish and Pocky Stick) as weapons, he/she gets another achievement worth 10 Karma.
The third boss appears at level 25, called Tondeiru Josei, who is Heikinteki Josei's sister. If a player defeats her, he/she receives a weapon (Daikatana, 20.57 DPS / Slow Speed), gold and experience, and an achievement worth 10 Karma. If he/she defeats her while the ninja holding the Daikatana is still alive and attacks her, the player gets another achieivement worth 10 Karma.
The last boss appears at level 35. It is quite strong and near impossible to defeat. It is called Mecha-Genbu. If a player defeats it, he/she finds a weapon (Laser Visor, 47DPS), lots of gold and experience, and an achievement worth 10 Karma. If the player defeats him after he launches his nuke, but before it lands, he/she earns the stamp "Nuclear Arms Race," worth 10 Karma. If he/she defeats him after the nuke lands and survives it, the said player gets the achievement "We Had a Falling Out," worth 10 Karma.The nuke takes like 2 rounds to blast at your ninjas.I will be wise to have at least 3-5 black,pink tip and 40+ weps if your a Shodow or Lotus Clan clan you should have more for damage to slay the mighty Mecha Genbu But Fire Must need 3 Purple Tipped belt or if you think you had lots of health and power go for it to Slay the mighty Mecha Genbu...