Lethality Thresh is a non serious/fun played build that is used often due to its immense damage early game, and how he can scale with damage much longer than most pure damage builds. His early lethality balances his Magic Damage and Physical Damage and combines the two to do immense damage quickly, and when he lacks in attack speed he makes up for in 2 shot potential later game. When you finish with your lethality and buy the critical strike items, thats when the one shots come in to view. Lethality Thresh is the Ultimate Glass Cannon that destroys glass cannons with simple placements and timing.