Faction Damage Bonuses increase damage done to all enemy types of the corresponding Faction, including Bosses. It is calculated as a total damage multiplier against the faction in question.
Faction damage bonuses increase the weapon's raw damage and applies a second time to damage over time (DoT) from status effects created by it (dubbed as "double dipping"). For complete mechanics see Status Effect.
There are a total of 20 regular faction mods, each except The Murmur having a primed variant. 4 mods (Grineer, Corpus, Infested, Corrupted and The Murmur) for each of the 4 main weapon types (Rifle, Shotgun, Pistol and Melee). Damage is increased by 5% per rank, up to 30% for regular mods and 55% for primed ones. The base equip cost of each mod is 4 and they all have a polarity. Damage of Sacrificial mods is the same type as other faction mods.
Rhino expends 75energy to let out a forceful roar, increasing the damage output of himself and his allies within 15 / 20 / 22 / 25 meters. Rhino and affected allies gain 10% / 15% / 25% / 50% bonus damage to all weapons and abilities over a duration of 30 seconds.
The damage buff is considered Faction Damage Bonus, additive with other sources of Faction Damage, and multiplicative with other types of bonus of damage.
For example with a Warframe modded with maxed Intensify, and weapon that inflicts 100 damage per shot, a max rank Roar will increase the total damage to 100 × (1 + 0.5 × (1 + 0.3)) = 165.
With a weapon modded with maxed Serration, which inflicts 100 damage per shot, a max rank Roar will increase the weapon's total damage to 100 × (1 + 1.65) × (1 + 0.5) = 397.5.
With a weapon modded with maxed Serration and maxed Bane of Orokin, which inflicts 100 damage per shot, on a Orokin, a max rank Roar will increase the weapon's total damage to 100 × (1 + 1.65) × (1 + 0.5 + 0.3) = 477.
As faction bonus damage, the bonus is used twice in the calculation of status damage.
For example, with a weapon that inflicts 100 damage per shot, that procs a slash status, a max rank Roar will increase the damage per tick from the slash to : 0.35 × 100 × (1 + 0.5) × (1 + 0.5) = 78.75.
With a Warframe modded with maxed Intensify, and weapon that inflicts 100 damage per shot, modded with maxed Serration and maxed Bane of Orokin, that procs a slash status, on a orokin, a max rank Roar will increase the damage per tick from the slash to 0.35 × 100 × (1 + 1.65) × (1 + 0.5 × (1 + 0.3) + 0.3) × (1 + 0.5 × (1 + 0.3) + 0.3) = 352.6819.
Piercing Roar is a Warframe Augment Mod for Rhino that gives Roar the ability to inflict knockdown and 5 Puncture procs on enemies. Additionally allows Roar to be recast and passively increases its range.
Increases the damage any ally deals from any source, so weapon damage as well as ability damage for the duration of the skill.
To gain the buff the ally needs be in range at the time of casting, entering it afterward will not grant the damage boost.
The ally does not need to stay in range to keep the buff for its full duration.
Regardless of the range the caster will always get the buff.
All Sources also include the tick damage of status procs like slash or gas, which means that DoT status procs -- slash, heat, toxin, and gas clouds -- all get affected twice, in the same way as faction-specific modifiers would affect status effects.
Multiple Roars do not stack.
A stronger Roar will overwrite a weaker one.
However if a weaker is cast, so that it last longer than a stronger (i.e., it is cast right before the stronger ran out or has higher duration due to increased Ability Duration) it will boost the damage after the stronger ran out.
Notes[]
Paracesis has an innate passive (unlocked at each rank above 30) that will increase its damage against Sentients.
Trivia[]
Faction damage mods for Infested, Corpus, and Grineer were added in Update 9.0 (2013-07-13), while Faction damage mods for Corrupted were added in Update 21.0 (2017-06-29).
Grineer, 
Corpus, 
Infested, 
Corrupted and The Murmur) for each of the 4 main weapon types (Rifle, Shotgun, Pistol and Melee). Damage is increased by 5% per rank, up to 30% for regular mods and 55% for primed ones. The base equip cost of each mod is 4 and they all have a 
polarity. Damage of Sacrificial mods is the same type as other faction mods.
Narmer counterparts. For example, 
Bane of Grineer will work on Lancer but not on Corrupted Lancer or Narmer Lancer.
Sentient
The Murmur
75
Strength:10 / 15 / 25 / 50 %
Duration:30 s
Range:15 / 20 / 22 / 25 m
Paracesis has an innate passive (unlocked at each rank above 30) that will increase its damage against Sentients.
