After killing an enemy ward, a friendly Zombie Ward is raised in its place.
Azir is a champion who rapidly casts abilities thanks to his auto-attack nature with [W]. Because of this he is able to repeatedly cast Comets with relatively high hit-rate thanks to the slow on his [Q]
Azir is a champion who typically doesn't opt for a mana item, rushing Nashor's tooth and Magic Penetration. Manaflow allows you to supplement that loss of mana sustain and continue pumping out damage in the early to imd game.
Celerity's bonus Movement Speed allows you to better position yourself so that you're able to repeatedly attack with [W] in teamfights.
Scorch provides fantastic early game harass potential so that you're able to keep your enemy laner in kill threat at all times with your jungler.
Azir is a champion who loves to trade early and often from distance with [W]->[Q], because of this Cheap Shot allows you to take those trades and remain healthy for early game skirmishes around the mid lane.
Zombie Ward provides all-around excellent and consistent vision control around the mid lane, allowing you to keep better tabs on the enemy jungler.