Don't panic!
Lets put this in perspective.
I think we can all agree that Android OS needs to be running 100% of the time, 24/7, to make the phone work.
Therefore, if nothing else whatsoever was running on the phone, the Android OS figure would be 100% as it would be the only thing consuming battery.
However, as other processes are run and consume battery, in tandem with the Android OS, they too will be consuming a percentage and the Android OS percentage in relation to total battery consumption would decrease from 100% (since, contrary to popular belief, you cannot have more than 100% of anything).
So, the more things that are running and sharing battery power, the smaller your Android OS percentage will be.
You may notice that in the mornings, when the phone has been quiet all night (unless you schedule backups with Titanium, etc.) the Android OS will be showing that it consumed a large percentage chunk.
However, as the day goes on and texts are sent, calls received and made, GPS/Maps used, web browsing, screen on, display, etc. the percentage of Android OS for battery use will decrease in relation to overall battery usage.
Looking at your screenshots
AmitX123 I can see that in the period shown... about 2 days... you hardly used your phone at all.
You charged it 8 times.
You were connected to WiFi for about 95% of the time (indicating that you did not move away from your WiFi source and that your phone signal as a consequence was rock solid and steady... so, no searching for WiFi and phone signal much in that period). This is where your battery drain comes in because although your phone was only Awake about 20% of the time, your WiFi was on 95% of the time... thus draining your battery. I would suggest changing your WiFi sleep policy in Advanced settings.
Your phone was Awake for only about 20% of the time.
Your screen was on for about the same amount.
You probably made one, maybe two, short calls in that period.
So, the only thing running all the time would have to be the Android OS and this is reflected in the 85% usage.
This does not mean that you have a problem with Android OS, apart from WiFi. It simply means that you did very little with your phone and so the lions share of battery consumption would obviously be Android OS.
If you don't believe me... try charging your phone to 100%... make a note of the Android OS usage and then browse the web for 15 min's whilst playing music in the background and check your location on Google Maps and then see what percentage your Android OS shows.
I hope this helps.