252 SpA Life Orb Delphox Fire Blast vs. 252 HP / 0 SpD Assault Vest Chesnaught: 361-429 (95 - 112.8%) -- 68.8% chance to OHKO
This calculation is what made me do this. There's this fact that has been proved that Greninja is the strongest as it carries Extrasensory for Chesnaught, while Chesnaught is in the middle as utility support is very good, plus it gets Bulletproof to cement itself against attackers like Gengar. Delphos however has no such aces,if it ran Assault Vest then you might as well forget about the Magician ability it has.
Therefore, this answer is not incorrect, it's just proving that Gamefreak wanted to balance them out, it was just that they couldn't make major differences, so it can be told as Gamefreak's best attempt to b alance them out - giving it a 4+ BST in a stat (presumably sp.def).