Use "Upstart Golden Ninja" to Special Summon this card. Then use this card's effect to add another "Upstart Golden Ninja" to your hand, and overlay both for a Rank 4Xyz Monster.
Use "Summoner Monk" to Special Summon this card. Activate its effect, since they are both DARK, you can Overlay both for a "Evilswarm Nightmare", or any other Rank 4 Xyz Monster.
If you search for "Ninjitsu Art of Transformation", you can summon "Mist Valley Apex Avian", which allows you to negate any effect if you return a "Mist Valley" card. This can be a deadly set-up on the first turn, especially if you have "Divine Wind of Mist Valley" in your hand. You can essentially negate any two effects that activate during your opponent's next turn by just returning those two cards to your hand.
You can also use "Ninjitsu Art of Transformation" to summon "Dark Simorgh" and lock down your opponent's ability to Set cards. If you have "Anti-Spell Fragrance" face-down, you can use it to stop your opponent from playing Spell and Trap Cards entirely, gaining a significant advantage.
If you search for "Ninjitsu Art of Super-Transformation" instead, you can summon "Dark Horus" whose effect will activate when your opponent activates any spell card during their turn, allowing you to special summon "Hanzo" and use his effect to search any "Ninja" in your deck other than himself.