Myrmidon Secutor

The scariest Techpriests.

Axe Happy Mecha-Nerds
Secutors are battle-crazed Techpriests deployed alongside Destructors for the same reasons: The vandalism of Tech or the unjust death of Mechanicus personnel. Whereas the Destructor is a ranged murder machine, the Secutor is a close range beast, carrying one or more Chainaxes and tools to butcher the enemies of the Mechanicus, with maybe a few laspistol mechadendrites in tow.

RIP AND TEAR FOR TECHNOLOGY
In unison with Destructors, Secutors make a fearsome sight and a fearsome foe. While the Destructor fires away from range, Secutors charge into battle with all the zeal of a Khotnate, tearing into their foes with wicked weapons and improvised tools of death. If you're doubly unlucky, they'll carry a stunning implement to easily kill you.

Tripping the Charging Deathpriest
To defeat a lone Secutor, you just need to stay the fuck away from it. Fire away at range, and his systems will eventually sustain enough damage to fail. Melee combat with them is tantamount to suicide, as they have the health of a plated Mech, so ALWAYS stay at range. Make sure to dodge if you see them use a stun implement, because the second you go down, you're dead.

With a Secutor paired with a Destructor, it is completely necessary to kill the Destructor first. With ranged support out, the melee fanatic can just be kited. Just be wary of stun implements.