We have a Japanese idiom, “鬼に金棒- oni ni kanabo,” of which literal translation is “let an ogres get an iron club,” or an ogres carrying with an iron club.
For instance, the United States of America has (or had) been seen as an “oni ni kanabo” country that owns vast land, abundant natural resources, extraordinary wealth, plus the world’s strongest military power.
If China endowed with vast land and huge population gets much wealthier and strengthens military power, it will be oni ni kanabo – invincible country.
Is there English phrase(s) to mean the same effect – something that makes already strong one much stronger or invincible, or something that adds a telling strength to already strong one?
I’m looking for the saying to account for the strong gets absolutely strong, like Achilles gets iron tendons, not the average gets strong.