Critical
Obsidia's lifesteal is overpowered with this item set but you need to play carefully
Reap
Assassin emblem for high damage and penetration Swift for attack speed Weapon master to increase damage War cry since it suits her combo
Battle Spell
Flicker is a good spell for obsidia because she doesn't have an escape skill, her second skill is just a high burst of movement speed and it cannot pass through walls
Farming and pushing
In early game farm minions, prioritize minions over jungle creeps to make stacks faster Use Obsidia to push, her damage to turret is insane if used correctly
Best With Angela
Angela provides support to obsidia while obsidia is using her ult, she can also slow the enemy that obisida used her ult
Watch Out For Karina
Karina can easily immune her basic attacks even if she uses her ult and even if karina cannot ult her, she can still use the first skill to escape and evade attacks from obsidia