the reason for the armour runes is to give you the advantage in early game battles. this is my first guide and i use this build all the time for Varus, it is INSANE the amount of damage you can do in 1 second when you finish this build.

first you buy:
boots of speed - cause Varus is quite slow in the beginning

then, 2 health and 2 mana potions - because varus seems to run out of mana quickly early game

next buy the wit's end to re-enforce your blighted quiver and do an extra 40 damage early game.

buy the malady after that to do the damage faster.

then get the Madred's Bloodrazor to do an extra 40 damage, and give you an extra 40% attack speed increase, on top of that you now do 4% of the enemy champion's health.

Next you're going to buy Warmog's armor to give you an extra 920 health and health regen.

Lastly you're going to buy phantom dancer to put 30% crit chance on top of the 10% you get in your masteries. You really won't need the extra 30% crit chance until later game because you'll do about 400+ damage per second when you have around 2.0 attack speed.

Thanks for reading about my Varus build,
You will carry your team just as i do every game with this build.
please rate it and enjoy your game

-TehChrisKid