The Aeon Sentinels are titanic constructs created by Aeon to combat the Astrals and other Cyrathilians. These colossal machinas are made entirely out of Celsius metal and are powered by Archium energy.
The Sentinels are resistant to most blasts of energy and can therefore withstand a point blank blast of infernos energy from a Cyrathilian's Bukula and absorb it into their central powering unit thus making them even stronger.
Brute strength however seems to damage them and seems more efficient to use against them, though these constructs are extremely agile if not skilled in the art of close combat and are a challenge to even the most skilled Cyrathilians.