It seems like the titans have a really huge advantage like colossal, armored, female titan. They could probably charge at wall sina really instantly and take it down and wipe out humanity. Female titan spared Armin's life few times when she could take him out in seconds.

So it seems the titans are capable of killing all the humans completely but they don't. Why is that?

It seems like the Titans have a really huge advantage like the colossal, armored, female Titan. They could probably charge at Wall Sina instantly, take it down and wipe out humanity. The female Titan spared Armin's life a few times, when she could take him out in seconds.

So it seems the Titans are capable of killing all the humans completely but they don't. Why is that so?