This is a very versatile and mobile build for Yareli, if you want a more stationary team upkeep build take a look at my Pool of Life Yareli (https://overframe.gg/build/887940/yareli-prime/pool-of-life-[[Yareli]](/items/arsenal/5532/yareli/))

Playstyle and Survivability

The main way this build works is by casting Merulina with her augment [Loyal Merulina] to have her follow you around, provide 90% damage reduction and cast sea snares every 0.5 seconds all for simply casting your 2. You then run around with a strong secondary of your choice preferably a crit secondary (more into that later) and kill everything with pillage and Merulina herself providing very strong survivability hypothetically viable up to level cap (have yet to test).

Upon starting a mission:
Step 1. Cast 2 - Obtain 4 seconds of invulnerability and 90% damage reduction
Step 2. look for a group of enemies
Step 3. Cast 4 - Group them together (optional not actually needed)
Step 4. Cast 3 - Pillage shields and Armor, Obtain around 2.2k overshields
Step 5. Cast 1 - Use whenever you encounter a strong enemy like an eximus or just on a group of enemies, picks up and Stuns enemies while providing damage vulnerability
Step 6. Kill all enemies with your secondary
Repeat from Step 2 onwards

If your shields break OR Merulina dies:
Step 1. Cast 2 - 4 Seconds of invulnerabilty
Step 2. During the 4 seconds cast 3 to pillage shields and cleanse all status effects
Step 3. Optional - Cast 1 or 4 to stun or group enemies respectively to prevent them from attacking you or Merulina
Repeat whenever your shields break or Merulina dies

Mod Breakdown

[Growing Power] by far and none is the best in slot aura as applying any and all status effects with your weapons provides you with a 25% bonus to ability strength this strength is additive with other strength buffs. If you do not have Growing Power then Pistol Amp is a manageable replacement.

Primed Continuity is used to counteract the -60% duration from [Fleeting Expertise], you want close to positive duration so enemies affected by Sea Snares remain snared longer and your last longer.

[Umbral Intensify], and [Augur Secrets] are used to increase Ability Strength along with [Growing Power] and Molt Augmented, with all buffs active ([Growing Power] and 250 kills) you achieve 253% strength which if you need it allows for 2 cast armor strip with pillage. Another reason for increasing strength is increasing the damage vulnerability that is applied when an enemy is affected by Sea Snares this vulnerability is multiplicative with the Sea Snares that is cast from [Loyal Merulina] therefore if you cast Sea Snares onto an enemy that Merulina casted Sea Snares onto that enemy will take 2.53x * 2.53x = 6.4x more damage literally sextupling your damage.

[Fleeting Expertise] and [Boreal's Hatred] are here to [Reach] the 175% efficiency cap on [Loyal Merulina] allowing her to cast Sea Snares every 0.5 seconds, for reference with only 160% she casts it every 0.8 seconds and at 100% every 2 seconds. [Boreal's Hatred] also gives 65% shield capacity which is a very nice bonus as this [Yareli] is more shield tank focused then anything.

[Fast Deflection] and [Vigilante Vigor] are extremely powerful mods for shield tanking frames but since this build has an innate 90% damage reduction and pillage I am only going with [Fast Deflection]. basically both of those mods are used to regain your shields a lot more consistent if they break or if they take damage.

[Energy Nexus] is solely here as a nice quality of life mod so you dont need to use [Equilibrium] with [Synth Deconstruct] or use Zenurik focus school. This isnt really needed that much but again provided a very nice QOL since this is not an ability spam build and I never run into energy issues no matter how much im spamming Sea Snares. BUT if you dont want to use it then I would recommend replacing it with [Adaptation] for more DR (not needed in the slightest, honestly kind of a waste) or [Augur Message] (the better choice).

Loyal Merulina the bread and butter of this build, makes it so upon casting Merulina you dont start riding her like a K-Drive but instead you retain normal warframe mobility while she follows you around and casts Sea Snares every 2 seconds as default the cooldown scales with Ability Efficiency. Upon cast you gain 4 seconds of invulnerability, any damage taken during those 4 seconds is converted to bonus health for Merulina the most I have personally seen is 1.2 million. The 4 seconds is activated everysingle time merulina is SUMMONED not when you tap the ability Merulina has to be Summoned to achieve the invulnerability this obviously is one of your main ways of surviving high level content and is why theoretically level cap is possible

Arcanes

Molt Augmented is a must have for an additional 60% Ability Strength after getting 250 kills which persists until death

The second arcane I personally use is for buffing Secondaries. My go to picks are Arcane Velocity for more fire rate, Arcane Pistoleer for ammo efficiency if it is needed or Arcane Precision for more flat damage on headshot these are kind of personal preference but mainly depend on the secondary you are using

If you dont have any of the secondary arcanes or simply dont want to use them then Molt Efficiency is the best replacement

Helminth

Pillage is my personal favorite subsume of choice and this whole build centers around it and [Loyal Merulina] therefore I would not recommend using something else but if you dont have it or dont want to use it for some reason here are some other options

Airburst with the augment [Airburst Rounds] is very good as it is a grouping ability and provides a large damage bonus to secondaries I would recommend this subsume if you dont want as much survivability but want more damage || https://overframe.gg/build/891341

Roar, the all time classic. Provides a multiplicative damage buff to weapons and abilities

Breach Surge, makes it so enemies launch breach sparks upon taking damage or upon death which travel out to another enemy and does scaling damage based off the damage that dealt the final blow

Weapon Choices

I am simply putting my personal favorite weapons to use on Yareli no matter the circumstance

Dual Toxcocyst Incarnon || https://overframe.gg/build/887118
Kuva Nukor w/ Secondary Enervate || https://overframe.gg/build/891338
Sporelacer w/ Haymaker and Splat || https://overframe.gg/build/891276/sporelacer/[[Sporelacer]](/items/arsenal/5305/sporelacer/)
[Furis] Incarnon
[Lex Prime] Incarnon

Primaries do not matter at all unless you need headshots then use [Scourge]

[Praedos] and [Furax] are really good melees, [Praedos] for parkour velocity and more movement and [Furax] since it has the amalgam mod [Amalgam Furax Body Count] which just for having the [Furax] and the mod equipped gives +45% fire rate to secondaries