Bastion
BulwarkReality Tear
Passive: On cast, attacks gain 
stacking bonus magic damage. Starting from the third cast, gain true damage instead.
Active: Gain 
Shield for X seconds, then slice open a rift on the largest group of champions dealing the Passive's bonus damage to all enemies within. Enemies have their Attack Speed slowed while allies within gain Attack Speed, both rapidly decaying over X seconds.
The best build for Shen is Legendary Vex (S+ tier). Shen is a 5-cost champion with the following traits: Bastion, Bulwark. Recommended items for Shen are: Sunfire Cape, Protector's Vow, Adaptive Helm. Shen also features in these builds: Meeple Legendary, Space Groove Snipers, Primordian Marauders, Invader Zed, Reach For The Stars, Nova Marauder, Voyager Vex, Space Groove.
