Being one of the four Blues, it's the origin of many characters and the location of many islands. Here are some of the details that I found "European" about the North Blue.
🏰 Trafalgar Law and his family are from North Blue. His name has origins from the Battle of Trafalgar and the Battle of Waterloo.
🏰 According to oda if sanji existed in real life he would be french
🏰 The Montblanc family from NB being a reference to the Mont blanc. The highest mountain in the Alps and Western Europe, rising 4,807.81 m above sea level
🏰 Characters from north blue that tie with european culture trough their names origins :
From chapter 1034, we know that sanji always had this ability to increase the temperature of his flames but couldn't due to his own body. If we were to compare pre-exo sanji with car it would be :
🟢An SUV mitsubishi car with a lamborghini engine
Flames color have strong relation with the heat output. According to the kelvin color chart the weakest flame is red while the hottest flame is blue. Since its introduction, DJ evolved :
DJ was introduced as a move able to deal external damage by making fly opponents using sheer force but also as a move a to burn the opponents by the inside. Jabra even mentionned that the attack burnt through his fucking bones and tekkai
Ifrit jambe being an OVER THE TOP version of DJ as it combines multiple power ups :
Ifrit jambe :
Sheer power (exoskeleton + increased strenght + super speed) + Hotter flames sustained with (coa + exoskeleton)
Sanji would indeed be able to bypass kaido's skin and hurt him
Not to mention that Hell memories was in itself already able to deal "lasting damage" to queen's tough hide. A YC able to tank several hits by big mom.
THREAD : Why sanji unlocking COC makes sense in the story
I think all of whole cake and much of the character arc sanji has been going through the whole story can be used as a catalyst for unlocking conquerors.
I made a thread about it recently but to summarize, sanji comes from a family of failed conquerors in the literal sense. Germa once conquered the north blue and over the generations they have fallen from grace.
Judge designed his children to help him conqueror the north again and has been relying on technology, enhancements and the suppression of humanity to get to accomplish this. He views humanity as a weakness and he fears and detests this weakness in himself and his family.