Your Win Condition
Outscale him (especially after Tabi's).
General Strategy
Darius 'hard counters Rengar'. Rengar wins early if he gets an empowered combo. Avoid fighting in bushes. If he jumps on minions, use RWQ-Auto-Ghost to kill him quickly. If he heals with W, you can pull him back in (E), having forced him to waste his empowered ability.
Trading Patterns
You prefer longer fights than Rengar.
Wave Management
You should have lane priority after the first few waves.
Their Win Condition
Early burst and empowered Q one-shots. Healing with W (if empowered).
