Providence

Strategy
Providence is the final boss in the game and has 3 phases.

First Phase
In his first phase he will teleport to you with a downward slash if you are far away from him and hack at you with an advancing slash if you are close by. Both deal enough damage to warrant caution; however, both attacks are very easy to avoid simply by staying in motion (drones will not fare as well since they lag behind you; prepare for them to be crushed fairly quickly).

After every 3 teleport slashes or normal swings he will thrust his sword into the ground which creates a shockwave that will knock you upwards then stun you for a few seconds if it hits directly. You cannot run from the attack to dodge it as it has infinite range until it hits something whether it be the player or a wall. Note that ledges do not stop the shockwave as it will travel down "off" of the ledge onto the next floor underneath and keep going. This attack is easily avoided by simply hanging onto a ladder or using a well timed jump. If you've gotten Jetpack items throughout the run it should be fairly easy to avoid if you follow the pattern to see it coming.

Once Providence has used his Shockwave attack twice, he will stand still and start targeting you with many delayed projectiles. In solo runs this is extremely easy to avoid as all you need to do is stay mobile, you can even get hits in on him because he won't move or dodge any attack. In co-op runs be more alert to your team mates' positions and directions of movement as this attack will target all living players. Crossing each other's paths will likely result in one or both of you taking heavy damage from the explosions due to it being much harder to avoid unless you're well coordinated.

It should also be noted that Providence has a buff skill in where he shields himself after the 66% and 33% health marks, indicated by a floating shield icon above his head. Unless you can deal massive amounts of hits in very little time, it's generally recommended to avoid fighting him in this state as all damage inflicted upon him will only result in 1's, with the exception of damage-over-time effects such as Thallium and Rusty Knife. Barbed Wire and the Tesla Coil also do damage to Providence while he has this buff. Also, Acrid's Epidemic can still do damage over time, ignoring the "shield".

Second Phase
After beating his first phase Providence will summon 2 Gilded Wurms, each with their own health bar.

The red worm will first indicate its attack with a target reticule which is followed by a laser stream that starts at the target's position then homes in on the nearest player. It deals damage extremely quickly and should be avoided at all costs.

The blue worm fires a spread of 5 projectiles 3 times in a row. It doesn't do much damage and can easily be avoided when far away but if it hits you at point blank it can deplete your HP near instantaneously, so taking consideration of the blue worm's head is important. Its head has an extremely short turn radius and fast rotation speed, so staying away from it if is about to fire is best unless you can handle the damage.

Both worms  suffer from an extreme weakness similar to the Magma Worm albeit even more so due to their slow movement and not being able to plummet fast enough into invincibility. Their weakness is that they're multi-segmented and every single segment will take damage from attacks. Any skill that can hit multiple segments easily will make very short work of the worms.

To progress from this phase both worms must be destroyed so if you can't kill both quickly in succession, don't worry, as the phase won't advance until both are dead.

Third Phase
When you kill the Worms, Providence will come back, this time with 2 Sanctuary Guards.

His attacks are all the same as his first phase so use the same tactics.

However, Providence has a new trick in his final phase. His shield buff from his first phase not only guards him from damage, but also summons Umbra of Providence, which is basically a shadow version of Providence when he hits 66% and 33% health. This doubles the amount of attacks coming at you making the fight much harder for characters that have no way of attacking and staying mobile at the same time. Although the shadow can be killed to make the fight easier, it is not recommended to focus on getting rid of the shadow as Providence will create another after the 33% health mark. There is, however; a very dangerous attack to look out for from the shadow: when it gets to the part of the pattern where he aims at you with delayed projectiles, instead of easily dodged single target at your location projectiles, the shadow will aim multiple delayed projectiles all around your location making it much harder to avoid. It should be also noted that the shadow version of this attack instantly drops your health to 1 rather than doing damage, and should be avoided no matter what, even if it means you'll be getting hit by Providence. Running through Providence right after he attacks is not recommended, as his shadow has a delayed attack right after. The shadow will also not act like the typical shadow players can have; it is able to separate from Providence and attack other players altogether. Its attack timing can also become slightly off, filling the gap between Providence's attacks with its own.

It is possible, though very difficult, to recover after getting hit by the Umbra's shadow skull attack. The best way to do this is to teleport the Surgery Table to the bridge before engaging Providence. Upon being hit by the skulls, hurry to the Surgery Table, the heal provided will help you survive further attacks from Providence and its shadow. This is easier to do if you happen to have the Time Keeper's Secret or the Unstable Watch, which will additionally let you regenerate health for a few seconds.

Aftermath
"What... are you?"

''"You monster..." ''

''"How?..." ''

After beating his third phase everything is over, you can either take a breather and bask in the glory of your victory or hurry and hit the console and get out of there. Either way, congratulations, you just beat the game! If you have Bundle of Fireworks, they will spray when the console is activated, making victory all the sweeter (they also fire when activating the Gauss Cannon, Surgery Table, and Nano Chest, providing a bit of extra damage).

Tips

 * Using the Keycards on the rooms will let you bring helpful things into the boss room. Cabins - Nano Chest (Gives you use items during the fight or even before hand, it also refreshes at a slow rate), Med-bay - Surgery Table (Heals you, your team members, and your drones. (If they are also nearby the table)), Armory - Gauss Cannon (Deals heavy damage if you lure the boss onto the same platform as the cannon and activate it, the boss does NOT have to be in front of the barrel, it will still hit if he's on the cannon itself.)
 * If you climb near the top of the ladder on either the top left or top right platforms and wait for Providence to shoot his delayed projectiles at you then run to the other platform on the opposite side before he can move, his AI will glitch out and constantly try to move to you but only be able to spaz out on the ledge. This makes the fight extremely easy for any ranged characters, however, is completely pointless for melee focused characters such as HAN-D or the Mercenary as you will not be able to get at the boss either.
 * If you climb either of the ladders and wait at the top, Providence will attempt to teleport on top of you but will get stuck in the ceiling, with his feet one tile above the ground. He won't be able to hit you unless you jump (not even with the shockwave attack) but will think you're in range and continue attacking without teleporting again. If you jump and attack between his swings you can continue hitting him with impunity until he gets to his delayed projectile attack.
 * The Miner is one of the best characters for fighting this boss, especially solo, as his great mobility and decent damage output give him a huge advantage over both the boss and the Worms.  In addition, To The Stars makes a great counter for the boss's highly annoying sword teleport attack. Other good solo choices are the Huntress (who can run away and attack at the same time) and the Engineer (whose turrets can easily hold his attention for 30 seconds, letting you attack aggressively, and whose mines do good damage to the worms and distract the red worms laser beam attack occasionally). Acrid especially can blaze through this fight, Epidemic alone killing off BOTH worms (sometimes with a single cast). With the majority of Acrid's abilities specializing in DoT poison damage, Providence's shield buff poses little challenge.
 * The loader is a great character to use in this boss fight if you don't have the miner yet, as you can easily avoid almost all his attacks in the first stage. This is also effective if you use the toxic centipede item, as when performing his downslash attack he will become infected but not hit you if you keep moving constantly. In the third stage, if you find yourself stunned by Providence while his shadow clone is performing the explosive circles attack, you can usually escape by using debris shield and hydraulic gauntlet to avoid damage and get away quickly, as stunning does not seem to affect these abilities in any way (note that this may not be true in later updates.)

Soundtrack
Providence