Phalanx is particularily weak to fire based attacks.
Attack / Defence Patterns
Phalanx in itself is a harmless blob of darkness, having no real form of attack. It relies on its coating of Hoplites to attack you with spear throws and stabs (at close range). However, it can move, albeit slowly, to back the player into a corner, and release its Hoplites voluntarily in an attempted flanking maneuver. Phalanx has exactly 35 Hoplites upon spawning, but can regenerate them when they die, as well as create more to exceed the original count. As more Hoplites are slain, the remaining creatures will slowly move to cover the side of the Phalanx that faces the player, leaving the other side exposed.
- The Hoplites will re-spawn, after a period of around 2 minutes or so per small group of Hoplite, until the last one is slain.
They will also regenerate their health, if they re-attach themselves to the Phalanx, after being hurt.
- The Phalanx will also regenerate its health, if not attacked for a period of time, until the last Hoplite is slain.
Phalanx can be easily toppled by a class that primarily uses melee. Simply two-hand your chosen weapon, coat it with Turpentine, and attack Phalanx directly. Do not use lock on. If you lock on your mobility will be slightly limited when you need to heal or recover Stamina. Don't hesitate either. The worst thing you can possibly do is stand around hesitating while Phalanx pummels you with it's projectile attacks. Retreat back a few steps when your Stamina gets low, then rinse and repeat. Hide behind a pillar and heal when necessary.
Using this tactic you can often take out 4 or 5 of the Hoplites at one time as they all group extremely close together on Phalanx's body. This works best for the Knight, Priest, Soldier, Temple Knight, and Hunter classes. It also works with the Royal, Barbarian, and Wanderer classes although players using these classes will find themselves healing more often. The Wanderer class in particular has a very fast attack animation, but a half second wind-up between each hit that can cause trouble. This approach does not work well for Thief or Magician classes.
Use Firebombs to kill as many Hoplites as you can (you can find a total of 11 in 1-1 or purchase more from the Dregling Merchant for 500 Souls each). Run behind a pillar and apply Turpentine to your weapon. Sprint around to the back of the Phalanx and look for a side that's not covered with Hoplites. Burn the Demon until it's dead. Using weapons with both hands will decrease the chance of being stunned should you hit one of the Hoplites shields.
You can pick off Phalanx's little buddies without using Firebombs or Turpentine. Just run around the perimeter of the room and dodge the spears. Some of them will break away and you can get behind them and kill them off pretty fast since their backs are vulnerable. Just keep doing that until you've killed enough of them. As above, when a hole is formed hack away at phalanx. He isn't very hard.
For the Magician and Royalty class, the Hoplites can be easily taken out with Flame Toss or Soul Arrow. Keep moving sideways and kill them one by one, or run across the room to scatter the Hoplites, pick off stragglers on the way. Hide behind pillars to heal or replenish mana. Since the Magician class does not have a mana regeneration ring, buying a couple of Fresh Spice from Blacksmith Boldwin before entering the boss area is advised.
After beating Phalanx, you can return to the Nexus and talk to the The Maiden in Black. This initiates a scripted event which then allows you to speak to the The Monumental. After the event you will be able to spend souls on upgrading your stats.
Note for new players
Although it is possible to use Phalanx's Lead Demon's Soul to increase your amount of souls, be advise that Demon's Souls can be used later in the game to craft unique weapons, or learn unique spells. It is not recommended to consume them until you know what your options are.
New Game + Strategies
Any Large weapon Strategy
In New Game+ onward you should have a large arsenal of weapons. Among them may be the Dragon Bone Smasher, Great Sword, Northern Regalia, Demonbrandt or Soulbrandt. Any of these make short work of the Hoplites shields and do massive amounts of damage to the Phalanx itself. Using a weapon you can enchant such as the Dragon Bone Smasher is recommended because of the Phalanxes weakness to fire. So bring some Turpentine! After doing a combo of attacks make sure you have enough stamina left over to dodge to the Hoplite attacks. And repeat until you can get some hits on the Phalanx.
In New Game+ and onwards you can use a weapon that ignores shields, such as Blind, as an alternative to Turpentine coated weapons, because it will completely ignore Hoplites shields and kill them even faster than fire. After you kill all Hoplites you can switch to a more powerful weapon to finish up the remaining blob, as Blind will barely scratch him.
Large Sword of Moonlight
In New Game+ and onward, you can use the Large Sword of Moonlight against Phalanx to great effect. It ignores the shields of the Hoplites, making it easy to eliminate all minions. Phalanx will be reduced to a harmless roaming blob.
In a later play-through of the game (from New Game+ onward), the Phalanx can be taken out in seconds. Simply hide behind a pillar and let the Phalanx creep up near you and cast Firestorm once or twice at the most. This should take out any and all of the minions as well as the Phalanx himself. Soul Ray is also interesting due to it's penetrating effect. God's Wrath is also good, but only to get rid of the Hoplites.
It may sound odd at first, but the fact that the Phalanx itself is immune to Plague doesn't figure into this strategy at all. If you obtained Death Cloud on your previous playthrough, it's a simple matter of running straight to him, dropping a cloud directly on top of him and all of his little friends, then running about for a few minutes. The Plague damage will clear out all the Hoplites, leaving you free to stab, blast, or just sit and laugh at Phalanx's inability to attack you.
Please note, that using Death Cloud on Phalanx while in Online mode may cause a strain on the network connection, thus dropping Blue Phantoms from a host's world.
Soul Ray works beautifully against Phalanx, or rather, his swarm of Hoplites. One shot is likely to hit 4-7 hoplites and Phalanx itself. With a high enough magic stat it's possible to kill the hoplites with one shot each while dealing some damage to phalanx itself. It's easiest to circle around Phalanx and it's minions and wait until you see a group of them roughly lined or bunched up. Fire away and duck behind a pillar if you need to heal or restore your mana.