Percy and Annabeth's kids loved whenever 'Uncle Leo' came over.
Leo would always light himself on fire, so the kids would have an excuse to use their water powers on someone.
'Uncle Leo' would also bring over tons of candy and cookies, and feed them to the kids, even though Annabeth would tell him not to.
But Leo didn't care because it felt good to give these kids a wonderful childhood;
One Leo never really had the chance to have.
And Leo wanted them to know he'd always be there for them.
Even when Uncle Jason and Uncle Frank weren't.
Even when the world wasn't there for them, Leo was.