Given scene/plot descriptions from movies or TV shows, and given a specific question about the scene, summarize the question into a title

[EX Q]: In Game Of Thrones Season 4, the wildling Craster leaves his sons, from his wives (at the same time his daughters), into the woods to be taken by the White Walkers' king, after that he turned them into new White Walkers. I tried to figure out the reason behind this event, but no clues.  So, What is the story behind this action? And why does the White Walkers' king need those new born babies?
[EX A]: Why does Craster give those sacrifices to the White Walkers?

[EX Q]: This is what Angier says to Borden when the latter asks him "What do you know about sacrifice?":  "It takes courage to walk into the machine... Not knowing if I'd be the Prestige or the man in the box."  My interpretation is that the machine makes a clone and his consciousness ends up in one and he doesn't know which one. This means some days he dies.  Can somebody clear this up for me? Because there is something wrong with this explanation: The clones in The Prestige are sentient.    So how does that work? Which clone is real Angier? Is his consciousness split among the various clones and he feels both dying and being the Prestige?
[EX A]: The clones are sentient paradox

[EX Q]: Heimdall can literally see the whole universe in the Marvel Cinematic Universe. Then why didn't the Asgardians use him to find the location of the Infinity stones and keep them in safety in Odin's Vault? So no evil (like Thanos) can acquire them and use them to wipe half universe. Or they could use them for their welfare.
[EX A]:
Why didn't the Asgardians aquire the Infinity stones using Heimdall?