Thrax Killing

Thrax present a gear-check, as they are tough to kill but dangerous to leave alive. Plus, you want them dead for Arcane drops. They have Overguard so they cannot be crowd controlled until this is broken. They inflict Magnetic procs with their attacks. Thrax Centurions will perform a leaping melee attack where they dash across the room at their target, and are invulnerable until the animation completes. Thrax Legatus will float in the air and split into three spectral forms that shoot out magnetic lasers, and are again invulnerable until this animation completes (shooting the spectral forms with your Operator will interrupt the attack and speed it up a little). These attacks can make it easy to lose track of the Thrax in a room full of trash enemies, and they delay you from killing them.

When the Thrax's Physical form is killed, they perform a short animation as they enter their Spectral form, where they can then only be killed by Void damage from your Operator's Amp. Magus Melt and the Virtuos Arcanes do not help with Spectral forms, as Elemental damage does not damage them.

At 65 Exolizers and below, most Steel Path modded weaponry and any crafted Amp or Focus School can deal with Thrax decently quickly, though you will notice them getting tougher as they approach level 1000, and you may notice the strain on the Exolizer rotation as this slows you down. Beyond 65 Exolizers, the gear-check pressure increases drastically. Your options for weapon damage, Operator damage, and Warframe survivability generally get more limited.

Some build guidance is covered below.

General Thrax Killing

This section of the guide will cover the general information needed to kill Thrax.

Thrax Physical Form

• Use strong single-target weaponry.
• Armour strip is recommended if not using armour-bypassing damage.
• A Thrax's Overguard overtakes their health as they scale. At level cap their total health pool consists of ~9.5 million health and ~15.5 million Overguard. Magnetic priming is therefore recommended.
• Thrax have a weakness to Void damage, and have no resistances.
• Due to their Overguard, Thrax cannot be traditionally crowd controlled, but up to 4 Cold procs can be applied to slow them down for easier headshots.
• If Thrax's attack abilities are causing you trouble, you can prevent them from using them with Silence.

Thrax Spectral Form

• Headshots will greatly improve your Amp damage. After a Thrax completes its spinning Spectral animation, it will always be facing in the same direction as its Physical form "died" - use the animation to prepare and position yourself.
• If a Spectral form gets away from you before you manage to kill it, it will become extra vulnerable to damage while it tries to absorb a nearby unit to regenerate itself (colloquially known as The Slurpee). Use this short window as an opportunity to finish the job.
• Operators are vulnerable and cannot use Void Mode while shooting. This means you want to focus on short bursts of high damage, rather than longer sustained DPS, to minimise the amount of time your Operator is in the open and getting shot at.
• Once upon a time, Viral stacks carried from the Physical form over to the Spectral form. As this is no longer the case, Madurai's damage output shines very high above the other Focus Schools.