Turians adhere to a strict moral code: "The needs of the group outweigh that of the individual." Discipline is the foundation of turian society. A turian line never collapses; its troops fall back in order, setting ambushes as they go. You will only see a turian's back when they're dead.
Turians receive the best military training in the galaxy. Their proficiency with a wide range of weapons, as well as their unmatched focus and determination, make up for their lack of speed and agility. They are a redoubtable ally on any battlefield.
With Overload to strip shields and barriers, and Warp to chew away enemy armour, the Turian Sentinel is effective against any type of enemy. Combined with Tech Armor to reduce damage by up to 50%, explode to stagger enemies in close-quarters, clutch situations for escape, and increase power damage by 30%, the Turian Sentinel is a very balanced class.
By landing a Warp on a target that is still arcing from an Overload, you will produce a Tech Burst, dealing extra damage to an area as well as to the target.
The Turian Sentinel is a good choice if you are looking for a tough, well-armoured character who can offer the team heavy and constant fire support.
Sorting out what you should pick for your powers is quite possibly the most difficult thing you will be doing with the Turian Sentinel. Since all five skills are useful, you may be much more inclined to take all five, rather than maxing out four and leaving one skill untrained. If you want to be versatile, you will either have to sacrifice protection, damage, or endurance, and this can be quite a deterrent to invest in both damaging powers.
Turians lack agility so remember to use cover or accompany teammates when dealing with the more elusive enemies such as Nemeses or Phantoms.
Tech Armor's detonation carries enough force to stagger a Phantom on any difficulty, which can give you a few precious moments to run away so you can engage her at a more comfortable distance. Used offensively, the detonation can stagger a Nemesis as well, stopping her quick and often erratic movements so you can kill her with gunfire or followup powers from teammates.
Turian Sentinels are not as powerful against collectors but still a considerable threat due to the combination of Overload and Warp to tackle any foe.
Warp will destroy the enemies armor, health, or barriers, making them very vulnerable
Overload is not as useful for enemies with a weaker barrier, but will cause much more damage than warp on enemies whose barrier is much harder to crack. Alternatively if evolved, Overload will incapacitate weaker foes briefly, and perhaps give you the few seconds needed to dispatch stronger enemies.
Tech Armor needs to be kept on, as you will undoubtedly be taking a lot of damage from these ranged specialists. Cover needs to be stuck to as often as possible, since they cannot evade and will help keep your shielding intact.
Warp will be helpful against Brutes, Ravagers and Banshees, especially when evolved to do max damage to armour.
Overload can be employed against Banshee's barriers or Marauder's shields, but for most Reaper opponents you'll need your guns or Warp.
Tanking with Tech Armour and a heavy gun loadout can be viable against Reapers, as it allows the player to fire continuously outside of cover, while reducing damage taken by up to half.
Tech Armour can also be detonated to reliably kill Husks that have gotten too close, or stagger Marauders or Cannibals which get too close. Do so to prevent their melee attacks, which are incredibly hard to interrupt, deal significant damage on higher difficulties, potentially breaking shields in one hit, and they stagger every time.