The Infiltrator is a mix of Soldier and Engineer, being a tech-saavy agent who is equally at home targeting an enemy’s vulnerable networks or picking them off with sniper rifles. While the Infiltrator won’t become a full-fledged assassin-archetype until the sequel, it’s pretty clear where this class is leading. In addition to being able to debuff and damage enemies with Decryption, Electronics and Damping, the Infiltrator has access to Pistols and Sniper Rifles. Defensively, the Infiltrator can boast Tactical Armor, which will allow them to wear medium armor, and they can also unlock the Fitness tree, which grants them immunity. All this combines to not just make them to second most durable character in the game (yielding only to the Soldier), but perhaps the best overall class in the game, one that has a potent, diverse offense and a great defense.
Infiltrator Bonus Talent
The Infiltrator arguably has access to the best abilities the [Engineer] has; Decryption, Electronics and Damping, which can disable an opponent’s weapons, shields and biotics/abilities, respectively. They lack only AI Hacking, which, frankly, is no big loss.
Like the Soldier, you may be tempted to bolster their already potent defensive powers by grabbing Barrier, but they need it arguably as much as the Soldier does… which is to say, not at all. As it stands, the Infiltrator can only aspire to medium armor, but has bonus shields from Electronics and the same access to Immunity via Fitness, which will not reduce damage dealt to shields/barriers, making it incompatible with Barrier.
The only real “weakness” the Infiltrator has is the lack of biotics, which are useful for debilitating enemies… especially krogan. We suggest looking for an ability that can debilitate enemies, render them helpless, make them easier targets or perhaps deal some damage. Or you can just grab Lift and do all those things at once. Hard to overstate how useful Lift is, as it floats an enemy harmlessly in the air, unable to defend itself.
To unlock Lift as a bonus talent you’ll have to grind out Throw and Lift on another character before making your desired Infiltrator, but it’s a small price to pay to add such a potent tool to an Infiltrator’s arsenal. The only downside is that, despite possessing a biotic ability, your equipment potential will not be expanded to include a Biotic Amp. You’ll never be as powerful as a genuine biotic, but Lift doesn’t really need the boost to make it a great pick.
Throwing Lift onto an Infiltrator will give them the ability to debilitate any threat, something few other classes can claim… and unlike the Sentinel, the Infiltrator will have access to more than just a Pistol, medium armor and Fitness.
The sniper rifle is now potent without any talent investment, but if you want to make the most of it, you’ll need to drop five ranks in pistols, then three ranks in sniper rifles to unlock Assassinate, which will allow you to deal 3x normal damage with your next shot - ideal for picking off problem foes from a distance. If you want to advance further, you can keep dropping points in sniper rifles (Master Assassination will improve damage to 4x), which is nice, but not necessary. As for pistols, you’ll unlock Marksman at rank 3, granting you a +25% damage bonus (50% for headshots), which is… fine. The damage boost will increase to +75% (2x for headshots) when you unlock Master Marksman, which is probably a more worthwhile goal than maxing out sniper rifles.
Like usual, you’ll want to diversify early on, rather than specialize. Start out by grabbing a rank in Decryption, Electronics to score the Overload and Sabotage abilities, respectively (as well as Lift, if you have it). This will make your Infiltrator incredibly powerful immediately, as having three abilities you can toss out on a whim is pretty handy. Later you should drop three ranks into Pistols to unlock Marksman and three ranks into Tactical Armor for Shield Boost to give yourself another offensive option and a defensive option.
As you gain more levels and the maximum ranks you can invest in each talent tree expand, focus on Electronics to unlock Damping and Tactical Armor for both Fitness and medium armor. Once unlocked, grab Immunity from the Fitness tree to really round out your defenses.
Keep pushing Electronics and Decryption until they’re maxed to ensure you can unlock any item you come across (and empower two of your best abilities). Fortunately both of these will give you their master-tier abilities at rank 9, and there’s honestly not a whole lot of incentive to invest further, saving you some points. After that, you can unlock Sniper Rifles and advance in that tree enough to get Assassinate and drop points into Spectre Training to unlock Unity, if your squad hasn’t proven reliable enough.
By now you should be approaching mid-levels, meaning saving up for your specialization isn’t a bad idea. When you unlock it, max it out, as Commando will improve Immunity, Marksman and Assassinate, while Operative will improve OVerload and Sabotage. Both are worth getting, whatever your specialization.
By late-game, your build is already pretty solid. Drop points into Lift (if you have it) and Damping to improve their abilities, and consider maxing out either Pistols or Sniper Rifles, depending on your preference. The damage boosts Marksman gains as it levels up is more useful than Assassinate (perhaps because the base Assassinate ability is already so powerful), but it’s hard to go wrong either way.
You don’t really need to keep dropping points into most other talents - Tactical Armor is fine at rank 7 (although if you want Advanced Shield boost, it’s only a point away…), as is Fitness at rank 4. The +15% boost to damage reduction and +13% health just don’t seem worth 8 talent points. That being the case, the final dozen or so points can go into whatever you wish - maxing Charm or Intimidate (if you don’t care to be power-gamey and max them for free), Spectre Training for the Unity boosts and passives or your second weapon.