Perpetual Mechanical Array, strategies, weak points, and achievements

The Perpetual Mechanical Array is a boss found in an underground cave north of Narukami Island, in Inazuma; this Boss can be considered the equivalent to a Hypostasis that deals Physical damage instead of Elemental; defeating it will grant you Perpetual Hearts as well as Cryo and Geo Gems.

To reach this Boss, you can use a portal above Jinren Island or solve a few puzzles and the Sacred Sakura Cleansing Ritual questline.

Perpetual Mechanical Array Portal location

Interact with Electrogranum

Perpetual Mechanical Array Arena

Strategy

While this Boss is a cube that exclusively deals damage of its" Element," it being Physical, in the end, it's not a Hypostasis, and thus not immune to this type of damage, only highly resistant to it.

The Perpetual Mechanical Array is often open to attacks; you don't have to wait to expose any core during or after its attacks.

Some of this Boss' attacks rely on the distance between you and it, so if you constantly stay close or far, it won't do some attacks.

At the end of the battle, the Boss will shield itself and summon four random Ruin Sentinels; defeat the one with the runes around it, and the shield and the other Sentinels will fall, exposing and weakening the Boss to all elemental attacks and slightly to physical attacks.

Weak Point

This Boss does not have a specific weak point, nor is he vulnerable to a specific Element, only the Sentinels he summons, these expose their "Eye", hit it when it shines.

Destroying the special Ruin Sentinel on the last phase will considerably lower all the elemental resistances from this Boss, while Physical resistance will go from high to low.

Achievements

The Battle of Narukami Island

Defeat the Perpetual Mechanical Array in its weakened state.

Beat the Boss when it is still on the ground from the last phase; if it recovers before you can defeat it, wait until it repeats the phase and try again.

Core Breakthrough

Defeat a Perpetual Mechanical Array after paralyzing all 4 types of its Ruin Sentinels.

The keyword is Paralizing, you don't need to defeat all of them, just shoot them in the "Eye", each type of Sentinel exposes their "Eye" during specific attacks, often when charging for an energy attack.

Could All Uninvolved Machinery Please Leave Immediately?

Defeat the Perpetual Mechanical Array without defeating any of its Ruin Sentinels.

The opposite of the previous achievement; when the last phase starts, do nothing, avoid the Ruin Sentinels, wait until the Boss gets back up, then keep attacking it.

The Not-So-Perpetual Mechanical Array

Defeat a Perpetual Mechanical Array in Co-Op Mode.