When Kronos was a young Titan he dreamed of having a big family after the prophecy was given that his children would be his downfall he resigned himself to never accomplishing his dream because while he wanted a big family he didn't want to take the risk.

Even though he was married he refused to have any kids with his wife unfortunately the fates had other plans, no matter how hard they tried they continuously had kids, he had his dream come true but unfortunately it had a dark twist and instead of the joy he should have felt he felt sadness and self-loathing because his dream became a nightmare. In order to protect himself from the prophecy he swallowed his children because while he refused to kill them but they were too dangerous to live. In the end this plan backfired and allowed the prophecy to come true because of his actions to prevent it, it had come true. He had fallen into a self-fulfilling prophecy.

He learned his lesson from this though and decided not to ever listen to prophecies again and to do what he wanted to regardless of ' fate'.

It seems his children did not learn from his mistakes though, for when a prophecy was given that a child of the eldest gods would be Olympus downfall or salvation instead of allowing the prophecy to work for them and loving and caring for any child they have so they would love their godly parents and Olympus by extension, they do what they could to try and override the prophecy, in the end they end up making the same mistakes he made. Banning the Elder gods of having children even though they're basically man whores, the plan to control the prophecy fails in less than a it's just further proves he was right that prophecies only come true if you try to stop them.

All three of his sons end up having children, despite the law against it, even if technically Hades did not break the rules.

When Kronos starts to gain consciousness and awareness of the mortal world he realizes he has many Mortal grandbabies. And that the gods don't want them, well he wanted a big family in the first place, and anyways this is the best way to screw up a prophecy, look how avoiding them worked for him last time. 'No I'll keep all the grandbabies, keep them nice and safe from mean old monsters, and neglectful parents mortal and otherwise.

Hera,and hestia have no mortal children,

Demeter does and is somewhat good at making sure they survive but is overly obsessed with he immortal daughter to pay them much attention, so one or two disappearing won't go amiss he is sure.

But his sons… What is wrong with them.

One with 2 children lock out of time (like the titan of time wouldn't notice that he scoffs), 'though he has heard nasty things about mortal teens, and his own brats had disembodied him in what would be considered their teens', so maybe Hades had the right idea there he thinks, if they are children forever they are never to old for cuddles and story time after all.

Another with 2 children that were left with an abusive drunk mother, one of which is quite powerful for her age and the other one is barely older than a baby, (At least his children where all safe, maybe uncomfortable but safe and he always made sure to eat extra so they were well fed)

At least his middle son can pick a good mother, he might just keep her to take care of the grandbabies, (and his wife might like another mother to talk to. !! Maybe Rhea will let me back into bed with her if I bring her lots of their precious grandbabies to spoil!!) The child is strong though worryingly strong, and is being raised in a monster hotspot. He is maybe 3 and already feels like a mature demigod power wise, and because of stupid 'laws' is not being trained, the poor toddler is going to flood the city if his powers keep growing it this speed, the little one might even ascend (use powers to freeze age/ become demi-immortal) in an effort to use up some of that wild energy pouring off his in waves, without an outlet who know what could happen (maybe his brother will be willing to train him, if only to spite Poseidon).

Yes, if his children can't take care of them, he will. Yes, they will love him and call him grandpa, give him cuddles and listen to stories of the good old days, yes that sounds much better than ruling asshole immortals, and wagging wars. ( he may or may not be rubbing his hands together cackling evilly, ehem, grandfatherly)

So Kronos uses his powers to shape a body, it can't handle much power but that is fine. He only needs it to take care of children not wage war.

Who needs war when there are grandbabies in need of cuddles,( maybe they can be ageless grandbabies too). Turns out his dear wife is quite pleased with his career change.