Inaros is a very strong tank, who do not rely on shields (he does not have any!) but instead has a huge health pool and strong bonus armor + several health restoration and crowd-control abilities. At level 30 he has 2200 health points - by stacking health mods you can easily reach 7-8.000 health! Furthermore, Inaros has three (!) abilities that will restore his health by doing damage to the enemies. If you know how to use his abilities and have a decent build, it is almost impossible to get killed when playing Inaros.
I recently kept dying while playing Rhino Prime despite my 2 Forma 8000+ Health Iron Skin.... I then switched to Inaros (with no Forma) and finished the mission without dying a single time. And I didn't even know how to use all his abilities at that time. Inaros can easily survive a tough fight even in the hands of a noob, lol 😀
If Inaros is killed, he will be encased in a sarcophagus, where he will not be able to use his secondary weapon as you normally do during bleedout - instead he can target nearby enemies (or allies) and siphon health from them. If there are enough nearby enemies so he can siphon enough health before the bleedout timer expires, Inaros will be able to resurrect himself - even on solo missions.
However, Inaros is not perfect: IMHO the Sandstorm could use a rework as this crowd-control ability sucks compared to Rhino and Nezha because 1) it is a channeled ability and 2) it hurls the enemies around, which make it difficult for allies to shoot them. Both Devour and Sandstorm are channeled abilities making Inaros gameplay stop-and-go which I find annoying in a fast paced game like Warframe. Nezha and Rhino allow for a much faster and more dynamic gameplay = more fun.
How to get Inaros
All blueprints are obtained by doing the Sands of Inaros quest - to start this quest you must buy the quest blueprint from Baro Ki'teer, the Void Trader (price: 100 Ducats + 25.000 credits). For more information read this guide.
Alternatively you can also buy blueprints from Cephalon Simaris for Syndicate standing - doing the quest is however much faster and more fun than farming all the Syndicate standing needed!
Currently there is no Prime version of Inaros.
Inaros passive ability is restoring 20% health when killing an enemy with a finisher attack (Ground Finishers and Paragon Mercy kills does not proc this passive).
Furthermore, when Inaros dies he does not enter the usual bleedout state - instead he is incapacitated in a sarcophagus and is able to revieve himself by aiming at a nearby enemy (or ally) and siphon life from them.
1: Desiccation will stagger and damage all enemies in a cone in front of Inaros. Enemies facing towards Inaros will also be blinded and open for melee finisher attacks. The damage-over-time restores 25% of the damage as health to Inaros.
The damage (and thus healing) scales with Ability Strength. The duration and range scales with Ability Duration respectively Ability Range.
Augment: The Desiccation's Curse augment mod has 75% chance of summoning a Sand Shadow (similar to Sand Shadows from the Devour ability) when killing a blinded enemy with a melee finisher attack.
2: Devour traps an enemy in quicksand, where they will not be able to move or attack. While the enemy is trapped you can press the Interact button (default X) to devour the enemy - while you devour him, you are invulnerable to damage and status effects (however, your companion is not!) and will restore health over time. If the enemy is killed by the Devour ability, he will become a Sand Shadow and fight for Inaros.
The damage scales with Ability Strength. The duration and range scales with Ability Duration respectively Ability Range.
3: Sandstorm is a crowd-control ability that traps nearby enemies in a violent sandstorm dealing Slash damage over time. Inaros is not able to attack or cast other abilities while channeling Sandstorm, also movement speed is reduced. With the Elemental Sandstorm augment trapped enemies will proc Status effects on the trapped enemies based on damage types and mods on the equipped melee weapon.
Augment: Elemental Sandstorm give the Sandstorm ability a 50% chance of causing Status effects on the trapped enemies; the kind of Status procs depend on the damage types on your melee weapon.
4: Scarab Swarm trades a percentage of your health for a strong Scarab Armor bonus armor. While channeling Scarab Swarm Inaros is immune to stagger, knockback and knockdown effects.
While the bonus armor is above 25% you can target a nearby enemy and hit the ability key again to launch a Swarm Projectile at the cost of some bonus armor; the projectile will infest enemies within range with scarabs causing a panic and dealing damage over time - this damage will heal Inaros and nearby allies. The Scarab Swarm will continue to infect nearby enemies during the duration of the effect.
Damage and healing of the swarm scales with Ability Strength. Casting range and healing range scales with Ability Range - however, the spread range do not scale. Duration scales by Ability Duration.
The Scarab Armor bonus armor can not be removed by enemy fire but can be dispelled by getting too close to a "Nullifier" bubble or aura. Also falling off the map will reset the bonus armor. If an enemy dispells the Scarab Armor, the health used to channel the Scarab Armor will be returned to Inaros health pool.
Augment: Negation Swarm will drain some of Scarab Swarm's bonus armor in order to protect you from Status effects.
This is a strong tank build that I use when fighting the Profit Taker - there are a lot of knockdowns during this fight which is why I use the Handspring mod for this fight. Otherwise this is a pretty basic Inaros build with focus on stacking as much health and armor as possible + some Ability Strength and Ability Range.
For normal missions you can replace the Handspring with whatever you like, e.g. Power Drift for some more strength and you can also consider replacing Armored Agility with Streamline for some more efficiency if you would like to spam your abilities more.