Do alpha house cats eat kittens?
You might be asking yourself "do male cats that breed with a female that already has kittens kill the kittens like lions do?". The answer is , luckily, no. Male domestic cats are actually very caring to stray kittens, often if left in the wild, these cats will orphan stray kittens, and even share a majority of anything killed with them.
Male house cat
So no, male cats don't kill other male cats' kittens, although male cats will pwn the sh#$ out of other male cats to preserve their dominance over female house cats, this will never lead to death, but might lead to a few scratches.