Warframe H-09 Efervon Tank boss guide

Warframe's newest 1999 update is live, bringing the new H-09 Efervon tank boss alongside new factions, multiple new mods, new missions, a group of Tenno NPCs, a new Warframe called Cyte-09, and much more. It is quite normal for such large mainline updates to receive a new boss battle, and Warframe 1999 is no different.

The H-09 Efervon is a first of its kind where the boss switches its faction alignment in the middle of the fight. The boss starts as a Scaldra faction member but changes to the Techrot faction after the first phase. Now that the less interesting parts are out of the way, let's get into the mechanics of the H-09 Efervon and how you can defeat it.

H-09 Efervon Tank boss fight: Mechanics and Tactics

Take Dante and forget everything (Image via Digital Extremes)

The H-09 Efervon Tank is found in the Victory Plaza assassination mission in Hollvania and is the upgraded form of the H-04 Efervon encountered during the initial campaign mission. The boss features upgraded defenses and armament and is generally much more challenging than the campaign variant, as it spawns inside a 65-70 zone.

There is no special equipment needed to enter and fight the boss. As for recommendations, it is better to have melee weapons with a large reach and hefty damage for the second phase. When it comes to general DPS, any incarnon or Lich-specific weapon will get the job done.

For example, during my first clear, I went in with a bog-standard Laetum build and had no issues whatsoever. But before you fight the tank, you must reach the arena, which itself requires a bit of work. The mission begins just like any other Hollvania mission, and you start on your Atomicycle.

H-09 Efervon using its turret to attack (Image via Digital Extremes)

As you navigate the roads and alleyways of the city, you reach a barricade that blocks your access to the rest of the zone. The method to remove this barricade is as follows:

Kill the enemies near the barricade until one drops the Emergency Transponder.
Take the Transponder to the nearest terminal and hack it by playing the Hollvania variant of the Snake game.
Finish the hack and summon the Scaldra shock troopers.
Kill the shock troopers to obtain their Thermian RPGs.
Use these RPGs to blow open the barricade. Three shots should do it for the first blockade.

After destroying the first blockade, the next zone will have another barricade, which needs to be dealt with in a similar fashion. This time, the blockade will require five RPG shots to destroy instead of three. Once it's destroyed, you'll enter the H-09 Efervon's arena.

H-09 Efervon mechanics

H-09 Efervon using Corrosive projectiles (Image via Digital Extremes)

Although the boss has two phases, there aren't a lot of mechanics to go about, and it's not too complicated compared to other Warframe bosses either. During its first phase, the boss usually fires off a shot from its main cannon and spreads corrosive material around the arena to make movement difficult. None of these attacks are particularly strong and can be avoided rather easily.

The H-09 Efervon Tank has two health bars in its first phase but is invulnerable when it first appears. To remove this invulnerability, you must first destroy the green vents on the tank's body. There are eight vents in total, two each on both tracks, the front and back of its chassis. Destroy four vents in any order, and the tank will be damageable.

You can damage the tank in any fashion, but the most effective and efficient method is to use the Thermian RPGs you previously encountered. Scaldra shock troops will be dropping in throughout the fight and will be marked on the map. Kill them, repurpose their explosives, and blitz through its HP.

Warframes, a weapon to surpass Metal Gear (Image via Digital Extremes)

Once it has a sliver of health left, approach the tank and interact with the prompt to start a small cutscene to enter the second phase. In the second phase, the boss becomes a Techrot-infested quadrupedal enemy and often dashes around the cratered arena. Efervon's attack switches from ranged to melee and is quite erratic with no distinct attack patterns, so dodge often.

Techrot Efervon has three health bars, and the boss heals itself after each segment is depleted. There are no vents to destroy this time, so use your best weapon to blast away at its hp. Upon reaching 66% and 33%, Efervon will summon Techrot reinforcements and leech health off them. Kill them until none remain or the boss ends the leech phase to begin anew.

Efervon takes increased damage on all of its protruding limbs and the turret. However, these spots are hard to aim at during combat. Get the boss down to zero, and the route to the extraction will open up. Pick up your rewards and get going.

What is the H-09 Efervon Apex?

Similar to The Fragmented One boss you can encounter in the Murmur missions, H-09 Efervon also has a hard mode encounter. Like The Fragmented One, this empowered boss can only be summoned in The Steel Path mode and has its own special summoning ritual, if you will.

To summon the H-09 Efervon Apex, you need to find two special terminals with a green glow during each of the blockade sections. These need to be hacked and their minigames completed for the Apex variant to show up.

A walking tank is the least surprising enemy in Warframe (Image via Digital Extremes)

The differences between the normal H-09 Efervon and the Apex variant encounter are as follows:

The Apex fight is level-adjusted based on the number of players. It starts at level 225 for solo players and rises up to 300 with each added player.
Similar to Archon Hunts, Netracells, and The Forgotten One fight, Self-revives are disabled, and the bleed-out timer reduces with DBNO. Mission fails when everyone is dead.
Scaldra and Techrot enemies are replaced by their Eximus counterparts. (Great for those Calendar objectives)
H-09 Efervon Apex shoots magnetic puddles that disable Warframe abilities. These puddles can be spread around by other enemies in the arena.

For the Apex fight, most of these abilities can be practically ignored by Warframes that can generate Overguard, like Dante or Styanax. However, completing the Apex encounter in solo mode with Excalibur, Mag, Trinity, Volt, Nyx, and Cyte-09 will award players their respective Hex Accolade Glyph.

As for standard rewards, the Apex variant will award a single Steel Essence for each kill and an H-09 Efervon Apex Turret Sumdali on the first kill. If you want to fill your orbiter with comically small tank gun barrels, this is your chance.

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Edited by Ripunjay Gaba