We're all crazy here

• I mean it's already canonical Hades/Pluto kids can just. straight up kill you. Like literally Nico can just tap people on the shoulder and they get Thanos Snapped. Totally fucking dusted. Sometimes bones are left and he just starts controlling that but that seems to be optional. He does it like three times in Tower of Nero.
• Not to mention Nico also being able to just rip people's souls out of their still living bodies. Is that a Ghost King thing or a Hades kid thing or a combo from both? Who knows.
• All the different ways Big 3 kids can make somebody just. Explode. Zeus* kids can just build up air pressure, Poseidon kids can build up water/blood pressure, and Hades kids can just make your bones splinter and shoot out.
• I don't think Zeus kids would be able to mind-control people by controlling electrical impulses BUT they could just send several thousand volts directly through you via touch so like. That's not great.
• Bloodbending for Poseidon kids is obvious but Hades kids have SO many options to potentially control people. Puppet their bones? Control their actual literal soul? If you go the route of "shadows are connected to the person" then dragging somebody around by their shadow? Or given that Hades kids are heavily implied to just have nearly all abilities ghosts are said to, there's a decent chance they could Just Straight Up Possess You.
• Poseidon kids can control blood (and actually exemplified in canon - seemingly just about any bodily fluid, as Percy makes Achlys start choking on her own tears/snot). They could also theoretically completely dehydrate you in an instant.
• Zeus* kids meanwhile can. Make air bubbles in your blood or etc. Which is VERY bad for those of you who are unaware. Hades kids can probably just yoink all the metals out of your blood. Casually revokes your iron privileges. Poseidon kids are just yoinking your blood In General. Etc etc.
• And then yknow, the casual natural disasters stuff. Zeus kids making tornados and hurricanes? Plus the aforementioned just throwing massive amounts of electricity around. Probably also able to make dust storms and stuff. Poseidon kids making hurricanes and floods and earthquakes? Or being able to create geysers just wherever they want? Hades kids also being able to make earthquakes or just shatter the ground or create giant ravines and etc. And, yknow, ZOMBIE APOCALYPSE. And aforementioned insta-killing I guess. Bonus Hera kids probably being able to also do tornados and dust storms and etc, possibly moreso than Zeus kids.

1.01 - “Diamond of the First Water”