Don't know whether it's an expression, here's the raw though, 100 is written in its number form not the kanji form from what I see, but I am no expert and just basing this on the visual form of the kanji you linked, I could be wrong
Stephen also translated it like hundred times tougher
As opposed to the Ray scene, from what I can tell by looking at it, the Kaido scene has that kanji that you are talking about
And that's probably why it is translated as 'King of the Beasts' and not hundred beast