Luffy and Law give me Joyboy and Imu vibes without the doomed by the narrative 800 year old situationship that one party still cant forget.
Law seeing himself in Imu as someone who lost everything, and hating them because they let their hatred twist the world, and knowing that if he did not end up with Cora for those few months/years he would be the same.
Law who recognizes himself if he was raised by Doflamingo when he was a young child wanting nothing more then to destroy the world. He hopes that he wouldn't be able to do it even then, but Law still worries.
Luffy is his usual self, no random old creature gets to tell him how he and Law will end up. Luffy gets to chose his own fate, and he is going to live, beat up Imu so everyone can be free and be king of the pirates! He is not leaving Law behind in all that, and besides this joyboy guy never got to be king, so that's a skill issue that Luffy aint going to have.
Imu will continue to taunt them, so sure that yes Joyboy will live just as he lives again in this youth, but what price will it cost to the holder of the ope ope no mi? Imu knows from his own experience will give anything for each other, will die on foolish sentimentality that in the end will mean nothing, that no matter what one of them will be left behind!