Why, a mana tripler, of course
Here is a small Image which can convey some of the Design Philosophy: I Chose level 2 for this Ninja for various reasons: For starters, every Dragon Ninja has always been Lvl 5+, these high level monsters can be bricky and clunky, you rather them stay in the deck to be summoned by the transformation traps, than to be stuck with them in the hand, struggling to find tributes for them, which in many cases, isnt even optimal to tribute your other Ninjas just to bring them out
Longstalk Brawl Green removal often hinges on fight or punch spells that force combat between two creatures
What is the pull rate for Tentacruel
Even without topdeck manipulation, you can still do stuff like bin Portal to Phyrexia and then wait for the Refurbish to end the game on the spot
Then it turns out Reshef himself was controlling Sol/Pegasus and is the real Big Bad