Varus

Strengths

An early point in Blighted Quiver helps harass enemy champions and get killing blows on minions.
During short range fights it's sometimes best to fire Piercing Arrow quickly, rather than charging it to full power.
Try to take advantage of Piercing Arrow's very long range to snipe at enemy champions before a fight or as they're trying to flee.

Passive · Living Vengeance — On kill or assist, Varus temporarily gains Attack Damage and Ability Power. This bonus is larger if the enemy is a champion.
Q · Piercing Arrow — Varus readies and then fires a powerful shot that gains extra range and damage the longer he spends preparing to fire.
W · Blighted Quiver — Passive: Varus' basic attacks deal bonus magic damage and apply Blight. Varus' other abilities detonate Blight, dealing magic damage based on the target's maximum Health. Active: Varus empowers his next Piercing Arrow.
E · Hail of Arrows — Varus fires a hail of arrows that deal physical damage and desecrate the ground. Desecrated ground slows enemies' Move Speed and reduces their self healing and regeneration.
Ultimate · Chain of Corruption — Varus flings out a damaging tendril of corruption that immobilizes the first enemy champion hit and then spreads towards nearby uninfected champions, immobilizing them too on contact.

A suggested 5-lane lineup built around Varus, based on hero partnerships and role synergy — not win rate.