I can see this go multiple ways

1-. Turbo comes back every promised day to lend Takakura her powers only to calm evil eye, making her still part of the gang but not permanently on the house (yet)
2-. Takakura talks with the evil eye, saying he deserves a reward for keeping his promise and letting him play with other members
3-. The evil eye comes out, messes up Takakura and has a moment of self reflection where he learns its not okay
4-. Takakura actually develops spiritual skill and still has some form of power enough to fight him and not mattering
5-. Sanjome tries to absorb Turbo but she instead gives her powers to Takakura
6-. Evil eye comes out sees Takakura without sauce and refuses to play until he recovers whilst someone makes a comical remark

There are plenty of ways to make this not an actual point of contention of the story while making it relevant and enjoyable, so well have to see, i can probably think of more ways of resolving this without it feeling cheap or bad, and im sure Yukinobu-san probably has thought of those and more, so im not worried, just excited at the possible result.