Warning: Spoilers Off applies to these pages. Proceed at your own risk.
Fire and Ice
Jack is very protective of Ace after what happened to Sabo. When Whitebeard knocks him down, Jack nearly breaks the "no killing humans" rule and drops the temperature enough that some of the Whitebeards start freezing.
Embers and Frost
How utterly outclassed Blackbeard is against Pitch. Pitch mocks Teach and calls his powers "cute tricks" before tearing them away from him, leaving him in agony. Pitch then beheads Teach and the Fearlings created from Blackbeard's crew devour his body.
A speck of Black Sand in a small cut is enough to turn a person into a Fearling unless they are a Nature Spirit— in which case they will eventually die rather than turn. The only way to stop it is to cut off the limb, and even then there is only a second to react.
Law touches the Black Sand and falls into a nightmare. Flevance burns around him as a dead-eyed Lami reaches out to him and asks Big Brother if he wants to play with her.
In many, he's often betrayed, hunted, and/or tortured by his family and friends.
He is Buried Alive while Luffy watches. Luffy sees him begging for help and laughs at him.
He accidentally burns the Moby Dick, while child versions of Luffy and Sabo beg him to stop hurting them. Sabo calls him a monster.
He awakens on the Moby Dick with Bay and for a while it seems like she's the real Bay. Then she paralyzes him with an injection and inject him with other drugs that set his nerves on fire. He lays there and burns as she serenely poisons him with cyanide, all while telling him Whitebeard's death was his fault. Every time she says a new "crime" of Ace's, she injects him with another poison.
The Guardians and Mother Nature see Ace as a freak and declare he is a Fearling that needs to be destroyed. They let "other" Fearlings do the job, by tearing Ace apart.
Pitch kidnaps Law from the back of the group of Straw Hats. None of them realize Law is missing until it is too late and Pitch captures them all in his darkness.
The descriptions of Law's near-drowning. Luffy accidentally shoves Law off the Sunny. He falls into the ocean and sinks while paralyzed. He is completely helpless and can only pray for rescue. His breath runs out and his vision slowly darkens and his body lurches in pain as he drowns. As Jack rescues him and drags him to the surface, the surface of the water seems to get further away from Law and he blacks out.