Now that you are ready there are three ways to conquer the KBD (note this is with the recommended ranging level and use of ruby tipped (e) bolts) when not using the recommended level be aware that the runs will be shorten by 1-2 kills
1) with 2 or more high level combat(100+):
60-80 bolts are needed
This one or the large group are the most likely of the 2 routes that will occur.
Get right up to kbd(don’t be shy

) and protect from melee DO NOT use protect from magic it doesn’t work

(don’t ask me why I just know from testing). WHY protect from melee? Well as protect magic doesn't work and getting next to him and protect from melee means that at least some of his attacks are NOT hitting you... well less hits means less food eaten means more time staying killing.
Drink your anti-fire potion and ranging potion if you have them.
Turn on your auto retaliate(I hope you had it off in the Revnant invested wilderness)
Make KBD "dance" by forming a triangle around him it will reduce the amount of times he will hit you.
Eat as needed you will average about 1 ½ to 2 pineapple pizzas a kill.
If all goes well you should need a bank run when all the prayer pots are gone as well as food(which should be at roughly the same time).
Here is a nice example of how to do this notice that me and kudlev are right up and next to him(I wouldn't recommend doing this with just one partner as you will use more food and stay less time and increase the chances of dying(aka not break even) unless your lucky and get visage

.

2) with 4 or more(including self) similar combat:
100 bolts or more are needed
Exact same as above but you will use more food and will need to do bank runs more often.
Also instead of a triangle encircle KBD.
3) with a large group(5+) of high combat or a mix of high and similar:
80 bolts are needed
This is by far the easiest and safest route to go and the one I'd recommend if you have never done kbd before or are unsure if you can do it with your character.
Combat goes as before but you will use less food and will stay much longer.
Add another Prayer potion(4) and leave 5-7 inventory spaces blank
The amount of food varies but usually 1/2 to a full pineapple pizza per kill.
If all goes well you should need a bank run when all the prayer pots are gone as well as food(which should be at roughly the same time).
With all 3 methods you should get enough drops if you were to sell them on the GE you should break even.
IF you seen anything that doesn't sound right or need clarification tell me and I'll make it better
SPECIAL THANKS 
:
Kudelv
Craven Range