Lieutenant Lech Kril

"I am Lech Kril. My hammer awaits your skull."

- Lieutenant Lech Kril

Lieutenant Lech Kril is the boss of Mars, and a dual boss on Ceres alongside Captain Vor. A revered war hero clad in impenetrable armor and armed with his signature hammer and / abilities, Lech Kril is a formidable adversary for anyone who opposes him.
 * On Mars, he drops Frost's components.
 * On Ceres, he drops Trinity's components.

Appearance
Lieutenant Lech Kril wears a unique set of body armor and wields the Gorgon and Brokk. This fight comes in two phases, with different abilities and attacks for each.

Phase 1
Kril is completely invincible. He will use his Gorgon throughout the battle on ranged targets, though occasionally he will use a lethal Freeze ability. He will resort to his Brokk to knock a target away when they get too close. Alternatively, he will slam the ground with his hammer, casting Ice Wave. Both abilities guarantee a proc. Kril prefers to stand his ground and tank all firepower, unlike most Grineer personnel. He will gain immunity to players' attacks if they target anywhere else besides his coolant tank, although his immunity wears off over time without additional attacks of the same type. If he is attacked blindly and relentlessly anywhere else besides his tank, he will eventually gain complete immunity to all attacks. Attacking his coolant tank will seemingly deal no damage, but it will disconnect one of its tubes and makes Kril freeze himself when he performs his ground slam. Only after he freezes himself does his tank take real damage. Once enough damage is dealt to his tank, a tube is destroyed. Destroying all four tubes will make Kril vulnerable to damage and shift the battle to Phase 2.

Phase 2
Lieutenant Lech Kril will burst into fire and dispose of his Gorgon and equip his Brokk hammer, exclusively resorting to melee attacks while turning all of his based abilities into slightly altered  based versions. Alternatively, he may throw his hammer at medium range targets like a boomerang. Despite possessing heavy armor, his melee capability and speed increases by a great margin. He is capable of catching up to a Tenno and his swing speed is noticeably faster. One must be careful as his combination of attacks can down an inexperienced Tenno.

Strategy
Battle on Mars

You can lure Lech Kril into a room behind him. First you must destroy the two tubes on his back to be able to hurt him. The easiest way is to stay close enough to him to enable his hammer, basically force him to try to melee you with his slow hammer attacks. It is easier to dodge his melee attacks than to try shooting his back from afar, especially when you do the mission solo. Once he attempts to hit you with his melee, try to maneuver behind him to dodge his attack and shoot the pipes.

When fought on Ceres, you can lure both Lech Kril and Captain Vor into the room located behind them from where they were standing so that the overall boss battle can be dealt with ease and without interference from the troops on this map tile, provided the alarm has not been tripped.

Alternatively, irradiating Lech Kril using warframe abilities or weapon status procs will make enemies shoot at Lech Krill which can help deal enough damage to his tank and tubes.

Phase 1
It is recommended to always stay close to cover during this phase, as Lech Kril can fire many rounds at you very quickly, dealing significant damage. When Lech Kril begins shooting, you can also run towards him to force him to stop firing his gun and swap to his (much easier to dodge) hammer. Being struck by his ice abilities is quite deadly as well, since the cold proc will keep you from returning to cover quickly.

During this phase, never attack him blindly. Lech Kril is immune against any attacks that do not land on his tank. If he takes enough attack on his body within a certain amount of time, he becomes completely invulnerable and nothing can damage him at all.

In order to make him vulnerable, players must shoot his coolant pack, highlighted in a neon red on his back. This is easily done by baiting Lech Kril into melee attacking, then firing at the coolant pack while he recovers from his heavy swing. You will know you accomplished your task when one of the coolant tubes on his back comes loose and begins to flail about, spewing white foam.

As mentioned earlier, irradiating Lech Kril will make the Grineer shoot at him hastening the process of loosening his coolant tubes.

Periodically, Kril will use one of his ice abilities against you. If you have disconnected one of the tubes on his coolant pack, the attack will backfire and leave him frozen. While frozen, he's vulnerable to damage, though only a small amount. He will unfreeze automatically when a quarter of his shields have been depleted, which also causes the loose tube to detach entirely.

This process of loosening a tube and then waiting for his ice attack to backfire and make him vulnerable must be repeated until all four tubes are detached, at which point Phase 2 will begin. It seems a fast way for the ice attack to be done is to force his melee attack by going in close range and then moving away, several times if needed. He'll do it almost always the second time.

Phase 2
Kril is no longer invulnerable during this phase, but he becomes even more deadly due to his new Fire-based attacks. However, his slow and heavy moves can be predictable if you've paid attention to his melee attacks during the first phase.

Kril can throw his weapon like a boomerang, which can easily be dodged unless it happens to ricochet off a nearby surface. He can also charge you at high speeds, which will knock you down and deal high damage if it connects, so you should swiftly dodge to the side. If it hits you but doesn't kill you, you'll still be knocked down, which leaves you highly vulnerable.

The best strategy is to simply outrun him while firing as many rounds into him as possible until you and your team are the last ones standing. Be wary, though: if you move to place where he cannot melee you, Kril may defend himself from ranged fire by casting a flame barrier.

Rarely, Kril can use a fire shield to protect himself from abilities. This is more evident if Inaros enters his Sarcophagus and attempt to absorb his health.

Utilizing Warframe Abilities

 * Volt's Discharge can be used to stunlock Lt. Lech Kril for a while to shoot his cryopack.
 * Ash's Smoke Screen, Loki's Invisibility, Ivara's Prowl, Shade's Ghost, or Huras Kubrow's Stalk will cloak the player, creating a strong opportunity for you to damage his cryopack.
 * Ash's Fatal Teleport can be used to deal massive damage to Lech Kril during his frozen state and during Phase 2 (which can insta-kill him in normal/non-sortie assassinations).
 * Loki's Decoy, Saryn's Molt, and Nekros' Shadows of the Dead are also invaluable for distracting Lech Kril's gunfire while exposing him to attacks from the Tenno.
 * Frost's Snow Globe slows Lech Kril's ice-based melee attacks, allowing his target to walk out of the way while increasing the length of time when he is vulnerable during his first phase.
 * Rhino's Rhino Stomp can be used to disconnect the pipes without having to shoot the back.
 * Nova's Molecular Prime can be used to slow Kril to make it easier to hit his weak point. Her Antimatter Drop can also be used to disconnect his pipes, as its explosion can pass through cover and Kril himself.
 * Zephyr is probably the best "hard counter" there is to him. Using Turbulence you can ignore most of his shots from his Gorgon (and all of the other enemies around you). Using Tail Wind and Dive Bomb you can easily detach the tubes on his back without having to worry about landing tricky slam attacks. And Tornado will help you keep the random enemies off of you. If you get good enough at this, you can easily solo him without having to worry about finding a team.
 * Valkyr's Hysteria can be used to revive fragile teammates, as a distraction for teammates to shoot his backpack and tempt Lech Kril into using his ice wave to freeze himself. Also, Valkyr can hit his backpack by a melee attack on his back, although this may require more practice. While Hysteria is active, Valkyr's ground slam attacks have a massive radius, which can be utilized to easily smash the tubes without even hitting Lech Kril himself. It also makes Phase 2 laughably easy, as you can completely ignore Lech Kril's attacks and just beat on him until he dies.
 * Chroma's Spectral Scream used on Kril's back can easily disconnect the cryopack's tubes.
 * Limbo's Rift Walk can be used to avoid all damage from him and lure him into melee strikes to expose his coolant pack. Popping in and out of the Rift in tandem with his attack telegraphs can make this battle easy.
 * Third attack for Atlas's Landslide can destroy Kril's cryopack's tubes.

Trivia

 * Lieutenant Lech Kril is a revered war hero among the Grineer. While his assassination will result in increased stability for the solar system and intimidate the rest of the Grineer, Lotus dislikes the fact that it will also make him a martyr to his people.
 * He looked like a larger Grineer Butcher before, and wielded a Fragor instead.
 * Currently, there is a chance that a glitch could happen after one or more of his cooling tubes has been severed, causing the battle against him to become stuck on Phase 1, in which the Cryo pack cannot be damaged further. This glitch happens randomly, no matter which Warframes are present (tested)
 * Kril appears in the Warframe Open Beta trailer, though still wielding the Manticore, rather than the current Brokk.
 * He was the first boss to undergo a major revamp, receiving a more complex boss battle and unique voice-acting and animations.
 * Prior to, he used the Manticore instead of the Brokk.
 * He also was the first boss to have a special death animation. Prior to Update 8, on death, he would fall flat on the ground like a downed player before actually dying. It took a little time for him to bleed out on his own, but one could finish him to shorten the time. After Update 8, he now has a new death animation where he falls to his knees and collapses before erupting in a fiery explosion.
 * Lieutenant Lech Kril's taunt "And I will strike down upon (player name) with great vengeance and furious anger!" Is a reference to a scene in Pulp Fiction, in which Samuel L. Jackson states the same as a quote from the Bible's book Ezekiel 25:17 (Which was a dramatized version from the original Bible quote, "And I will execute great vengeance upon them with furious rebukes; and they shall know that I am the LORD, when I shall lay my vengeance upon them.")
 * As of, his shields can be damaged during Phase 1. Although he is still invulnerable, bleeding effect from Slash-based weapons will directly damage his health.
 * His rank is somewhat unusual for a supposed 'war hero', as Lieutenants are generally lesser-ranking commissioned officers in current military terms, only three or four steps above the lowest possible rank. It is possible that Kril has not been an officer for long, or that Grineer officers are assigned their ranks/titles on a different basis; perhaps based off the size of the force they command or their overall long-term experience, rather than personal combat experience. Alternately, his status as a war hero may be entirely fabricated as a propaganda campaign, and his title/rank chosen on purpose.
 * His body appears in the kuva fortress, it is unknown why this is as he would be on Mars at the time.
 * If Inaros attempts to absorb his health while down, he will put a shield up to prevent this, it's most likely he has heard of Inaros due to being on Mars.

Bugs
Lieutenant Lech Kril
 * When using Fire Wave or Ice Wave, the effect of his hammer impacting the ground will instead appear at the end of the ability. There are also no visual effects for Lech Kril pulling out his hammer after Ice Wave is used.
 * When damaged by a Puncture proc, the effect will never go away. This may apply to other procs.
 * Upon death, the explosion effect will trigger when all his health is lost, instead of when his body disappears, making it seem like his corpse vanishes from thin air. (It appears this only occurs when bug 6 also occurs.)
 * After the cutscene on Ceres, Lech Kril may wield his Brokk like the Gorgon for a moment. After the cutscene on Phobos, Kril will wield his Gorgon like the Brokk.
 * If any animation other than shooting and/or walking is playing when you destroy one of Lech Kril's coolant tubes, he will not flail around in a daze.
 * When his final coolant tube is destroyed, Lech Kril can still take damage after being unfrozen, and before beginning his second phase. This is exploitable to significantly shorten the fight during Phase 2.
 * When beginning his second phase, the burning ground and death explosion effect will play, along with what should only be the heat proc-esque effect.
 * When Lech Kril melee attacks you using his hammer with only one arm, the swinging sound effect will play a second time as he brings it back to holding position. When he is in his first phase, the Gorgon teleports into his hand when the second swinging sound effect plays.
 * Lech Kril will continue to speak to the player on Phobos even after he's been killed in the fight, so long as Vor remains. The same goes for Vor if Kril is still alive.
 * His "second-skin" quote has a typo, as "second-skin" should not be hyphenated.
 * During his transmissions, he is in his second phase, even though he always begins in his cold based first phase. This is also weird since ice can be seen in the background.
 * If you stay out of Lech Kril's notice long enough, he will stop tracking you. If you end up behind him, he will try to face you, but will ignore attacking you until you attack him, make a noise, or walk into his cone of vision. If you chose one or both of the first two options, he will slowly waddle around until his cone of vision perfectly lines up with you, where the battle will then continue as normal. He may also waddle around when he "tries" to freeze himself. He will also lose notice if he uses his flame barrier.
 * Rarely, Lech Kril will walk in a random direction and use Fire Wave wherever he is walking. It is unknown if this happens with Ice Wave.
 * When performing a charge attack animation, he will stumble, but won't move accordingly.