Simple and sweet, I am the one with whom you can compete

A sweet little thing,
lots'n lots I have killed,
I have diminished so many,
so many I helped to rebuild.

I have many minions,
but on the top, there are three,
controlled by each other,
they are not so free.

You can't get rid of me,
it's up to me when to bid you adieu,
do not get confused,be warned,
I will surely come for you

No one can stop me,
you are all my slaves,
you all are bound to me,

This was in the sandbox, as per suggestions, I tried changing first two stanzas. This one is really simple and sweet one.

• I am pretty sure the answer is sugar :) – Gintas K Sep 6 '16 at 10:26
• @GintasK I would love to read full explanation – smriti Sep 6 '16 at 10:29
• I don't understand people that answer in comments – bg6471 Sep 6 '16 at 10:29

Is it

Time

A sweet little thing,
lots'n lots I have killed,
I have diminished so many,
so many I helped to rebuild.


Time can rebuild something, or destroy/kill it.

I have many minions,
but on the top, there are three,
controlled by each other,
they are not so free.


Pretty sure it's the 3 hands of a clock/watch.

You can't get rid of me,
it's up to me when to bid you adieu,
do not get confused,be warned,
I will surely come for you


Time will come to take us to death.

No one can stop me,
you are all my slaves,
you all are bound to me,


No one can stop time, and we have no other choice than following it.

• Yup! you got it :) – smriti Sep 6 '16 at 11:44

My idea

Drugs

A sweet little thing,

lots'n lots I have killed,

I have diminished so many,

so many I helped to rebuild.

Excessive use of Drugs kills people.. Although, if used judiciously can cure people of allergies,etc.

I have many minions,

but on the top, there are three,

controlled by each other,

they are not so free.

Not sure about this... Maybe refers that ther are only a few life-threatening drugs while others might be purely medicinal..

You can't get rid of me,

it's upto me when to bid you adieu,

do not get confused,be warned,

I will surely come for you

People become addicted to drugs, hence, very dangerous.

No one can stop me,

you are all my slaves,

you all are bound to me,

We all take medicines since our childhood, which are a sort of drugs as well...

• Frankly I was waiting for this answer.(This is not the correct answer). +1 for explanation – smriti Sep 6 '16 at 11:06

Sugar?

A sweet little thing,
lots'n lots I have killed,
I have diminished so many,
so many I helped to rebuild.

Sugar can cause many diseases, like Diabetes, but it also helps other people with low sugar levels to 'rebuild'. Reference

I have many minions,
but on the top, there are three,
controlled by each other,
they are not so free.

There are many types of sugars, but the main three could be Fractose, Galactose and Glucose or Lactose, Maltose and Sucrose. Reference

You can't get rid of me,
it's upto me when to bid you adieu,
do not get confused,be warned,
I will surely come for you

Not so sure about this one... Maybe we can't get rid of it because almost every food has some sugar in it?

No one can stop me,
you are all my slaves,
you all are bound to me,