Lane sustain dueling and late game scaling.
Improved attacks and sustained damage
Attacking and moving builds energy stacks. At 100 stacks, your next attack heals you and grants increased MS.
Excess healing on you becomes a shield.
Takedowns on enemies grant permanent Attack Speed.
Deal 7% more damage to low health champions. Gain AD/AP after kills or assists.
Empowered abilities and resource manipulation
Gain 10% CDR when you reach level 10. Excess CDR becomes AP or AD, Adaptive.
Gain increasing amounts of AD or AP, Adaptive over the course of the game.
+9% Attack Speed
+6 Armor or 8 MR (match-up)
Fleet Footwork on Gnar grants great lane sustain for repeated poke and trades. The burst of Movement Speed also helps you to kite and maneuver to land more auto attacks.
Overheal paired with Doran's Blade and Fleet Footwork allows you to build your shield in lane to help overcome any incoming poke damage.
Gnar loves a lot of attack speed to abuse his range and proc his [W] as often as possible in melee matchups.
Between Press the Attack and repeated procs of Gnar's [W] you should be able to quickly whittle the enemy champion to 40% health and get the bonus damage to kill them.
The extra bit of CDR from Transcendence puts you at 30% CDR in the mid game for more [Q] damage trades.
Gathering Storm on Gnar allows you to build heavily defensively while still scaling into the late game as a carry threat on the backline.