Infernus has a pretty weak laning phase, he can be poked out pretty easily, so only take trades based on enemy cd's and keep farming. Ricochet powerspike is very strong so aim for that. You can go for glass canon instead of ricochet if already snowballing very strong
buy in order
                                
                                            
                                
                                            Gain Spirit Power and Spirit Lifesteal.
+16 Spirit Power
+20% Spirit Lifesteal
6s Duration 
                                
                                            
                                
                                            
                                
                                            
                                
                                            
                                
                                            Your bullets apply a debuff that amplifies your Spirit Damage against the target and grants you Spirit Lifesteal against them.
10% Spirit Amp (Conditional)
+20% Spirit Lifesteal (Conditional)
6s Debuff Duration
Buy in no particular order, but rush toxic bullets.
                                
                                            Your bullets build up a Bleed on enemies, causing them to lose a percentage of their current health over time. Also applies Healing Reduction on the bleeding target.
5%/sec Bleed Damage
-65% Healing Reduction
3s Duration
10.3% Buildup Per Shot 
                                
                                            
                                
                                            Increases the effectiveness of your Healing and increases your resistance to healing reduction.
+25% Healing Effectiveness
+15% Heal Reduction Resistance 
                                
                                            When the target takes Spirit Damage, they have their Spirit Resist reduced.
-12% Spirit Resist
6s Duration 
                                            
                                
                                            no particular order, rush ricochet
                                
                                            Your bullets will ricochet on enemies near your target, applying any bullet procs and dealing percentage of the original damage.
50% Ricochet Damage
2 Ricochet Targets
14m Ricochet Range
                                
                                            +45 Spirit Power
(Conditional)
0.8% Buildup Per Shot
18s Duration
                                
                                            
                                
                                            Increases the number of Air Dashes and Air Jumps that can be performed before landing from 1 to 2
                                
                                            Dealing Spirit Damage applies a stacking Spirit Amp that increases your Spirit Damage to the target.
+6% Spirit Amp per Stack
15s Duration
0.7s Max Frequency per Target 
                                
                                            
                                
                                            Upon casting an ultimate ability gain temporary Bullet Shield, Spirit Shield, and Spirit Power.
700 Bullet Shield
700 Spirit Shield
+40 Spirit Power
15s Duration 
                                
                                            
                                
                                            Your next bullet will heal you based on what target you hit.
30 Healing from Heroes
10 Healing from NPCs
                                
                                            Your Spirit Damage applies Healing Reduction. If an enemy hero dies under this effect, you receive a large heal.
40% Healing Reduction (Conditional)
350 Heal on Hero Kill
6s Duration
                                
                                            Reduces the duration of all negative effects applied to you.
35% Debuff Resist 
Active - 45s:
Purge all negative effects currently applied to you. If any effects were removed, gain a movement speed bonus.
Cannot be used while Stunned or Slept.
+3m/s Movement Speed
3s Duration
                                
                                            Deals Spirit Damage and Slows targets movement and dashes. Also Silences their movement-based items and abilities. Does not affect target's stamina usage.
70 + (0.59 * Spirit Power) Spirit Damage
30% Movement Slow
25m Cast Range
3s Duration 
                                
                                            
                                
                                            
                                
                                            Reduces the effects of enemy Movement Slow
+40% Movement Slow Resist
                                
                                            Curses an enemy - interrupting, Siliencing, Disarming, and preventing item usage.
3.25s Status Duration
20m Cast Range
                                
                                            For the next 4s, all your bullets immediately apply Silence. Silence prevents targets from using abilities. 
2s Debuff Duration 
                                
                                            Each hero kill grants permanent Weapon Damage (up to a max of 5 times). Death results in loss of 1 stack. 
Conditional: +10% Weapon Damage per Kill