I've got the perfection revenge for the Celestial Dragons.
After the war Luffy says not to kill them and gets into a massive argument with everyone, Magellan suggests sending them to Impel Down for rehabilitation. Everyone reluctantly agrees to this. Flash forward and Level 6 has been refurbished to look mostly extravagant the Celestials are excited but Magellan quickly leads them to an area that is rundown and says they will be living there. They are complaining and asking who the nice area is for and he laughs and says your special guard and point over to Doflamingo. Doflamingo scares them shitless and he goes over and grabs Charloss's sister and says
"Tonight you, tomorrow someone else. Until im done with you all."
several years later the celestials are humble farmers