Guardian Across Dimensions

I, Lin Ye, a professional savior, am currently working overtime in the second dimension. The first world, the contract cat girl Feiju, is very fragrant. But what about the easy daily life we ​​promised? Why is the beginning on hell difficulty? ! Moreover, why do these worlds seem to have been added with "Honkai" MOD? The mastermind behind the scenes is actually my resentment when I chased the fan? Fortunately, after saving the world, I was able to take my wife and cross out my teammates to continue through the level. It's just... Why do the BOSSs in every world say that I am the ultimate "key"? This novel and its characters are purely fictitious. Any similarity is purely coincidental and should not be imitated.