This is a guide to the bosses and mini-bosses in the game. This CONTAINS SPOILERS so don't read on if you don't want to know
Major bosses in RED
Minibosses in BLUE
If anyone has any alternate strategies please post them up and i'll add them to the topic.
Location: Start of apocalypse level
Trauma demons become a regular occurance towards the end of the game so its worth getting used to fighting them. They hit really hard so the key is to keep out the way with hit and run techniques.
If you dodge the main attacks the trauma demon should hesitate for a few seconds after each giving you the opportunity to hit it a few times and run.
Don't rush the fight on higher difficulties, simply take your time until you get the B prompt pop on screen when you can deal some pain.
Note: If there are crates, cars etc in the area throwing these at the Trauma demon is an easy way to hurt it without getting into danger range.
Location: End of the Apocalypse level
Straga is giant and is in a pit of lava so you can't hit him directly as he is. Get ready to dodge any incoming attacks, Straga pounds the ground and sends shockwaves down a direct line so when he does this dodge to one side to avoid it. He also has an attack where he grabs the street and shakes it, don't worry when he tilts it from left to right, but when he lifts it up double jump to avoid damage when he slams it back down again.
The attack you are waiting for is one where he throws three cars at you. Dodge them then throw them back in his face to stun him. When he drops down pound his face.
Rinse and repeat until you defeat him.
Location: You fight this guy at Samael's prison
These guys become regular enemies later in the game and on apocalyptic can dish out a lot of damage.
As with the Trauma demon the key to these guys is counter attacking. Taunt the Phantom General into attacking and then dodge out of the way and dash back in and start a small combo.
Make sure you dash out of reach again as soon as he starts pulling off another move.
Location: Twilight Cathedral basement
You meet this huge boss in the basement of the cathedral shortly after finding your first gear item, the Cross Blade.
The Jailer will be accompanied by some skeletal warriors. What's more he can respawn these by smashing his cage on the ground.
He does a lot of damage but is pretty slow so keep on the move and you shouldn't struggle.
His weakness is the three yellow spots on his shoulder. Use the crossblade to target all three and throw it to stun the jailer and make the small green zombie controlling him fall out. Charge in and pound this guy until the Jailer gets up then get out the way.
Repeat this three times to finish him.
Location: Twilight Cathedral
Tiamat is the first major boss in the game (ignoring the Straga who beats you in the first level).
To start off with Tiamat will be flying around the outside of the arena you are in breathing fireballs at you. Its worth letting her break some of the scenary as it makes the next phase a bit easier. To avoid the fireballs you can use the dash but i found it easier to jump slightly to one side.
Around the arena you will find inert bomb growths. Pick one up and throw it at Tiamat. It should stick to her. Run in close and use the cross blade to target a torch then the bomb growth. The bomb will blow up and send Tiamat crashing to the floor. Run in and combo her until she gets up then run away.
Once Tiamat takes off she will soar into the arena and try and take you out. Wait until she is scraping along the ground towards you then dodge to one side, she repeats this three times before returning to the original pattern.
Repeat the bomb growth process again to cause more damage. After she crashes and then gets up a second time get back as she will jump into the air and come crashing down destroying all the bomb growths.
The battle now takes place on the arena floor. Tiamat will walk around trying to slash you, dash in and hit her a few times before dashing away again.
If Tiamat jumps in the air back off as she will do a ground pound again. Also be ready over the B button as she attempts to pull off a quicktime attack. If you're quick enough you will stun her and get some free combo time, if you aren't she will knock you into the air and fireball you for high damage.
Once you have done enough damage B will flash on screen and you will finish her.
Location: Anvil's Forge
Ulthane can't be hurt by normal attacks so the key to this battle is building up your chaos meter as fast as you can.
As soon as it is ready transform into Chaos Form and wail on Ulthane until the battle ends.
Location: Anvil's Forge
Uriel is very quick but fairly weak so the key to this battle is to keep moving. A lot of Uriel's attacks involve a lengthy recovery period so you can normally pull off a few decent combos while she is down.
This encounter with Uriel is pretty straightforward so you shouldn't struggle much. Use Chaos form if you have it for an easy win.
Location: The Hollows
The griever is the first and last enemy you fight in the Hollows.
When you first encounter this boss you have the angelic cannon on the ground in the middle of the room to help you out. Pick this up and open fire on the boss while avoiding its laser beam, the beam goes up and down as it moves around the room so move under it at the high points. The boss should flee fairly quickly so you will struggle to lose even on apocalyptic if you keep the damage up.
When you encounter this boss the second time you have no cannon so it is a very different fight.
The Griever starts off with two main attacks, a laser beam which tracks you around the room and a ground pound that it will do whenever you get close sending you flying and making hitting it impossible.
The key to this sequence is the rail road cart at the back of the room. As soon as the fight starts run around using the tremor gauntlet to break all the crystals between the cart and the Griever.
One problem you may have is if the laser hits the crystals they glow red hot and won't shatter when hit. The best way to let them cool is to repeatedly charge the boss making it knock you back so they cool off without being shot again. Once it cools run in quickly and shatter the crystal.
Once the crystals are gone run back to behind the cart and push it part way up the room towards the boss. Hold the Y button to charge up a punch and send the cart flying into the Griever's leg.
It will knock the cart back and summon a bunch of insect like enemies. If you're quick you can get a second hit with the cart in before the insects readh you, otherwise kill them all and then hit the boss again.
The second hit will send the Griever crashing to its knees, run in and use the Tremor gauntlet to shatter the crystal guarding its heart.
Now get ready to dodge the falling rocks as the boss pounds the walls. I find dodging around the main room works pretty well.
Repeat the above process and attack the new weak spot until the boss goes down.
Location: Ashlands arena
In phase one the gladiator is riding your horse ruin. To beat him lock on and dodge his attacks until he gets close enough to hit, pound him with your sword and when he gets stunned unleash a combo or two.
When ruin rears up back off as he will do an area attack. When you get the B prompt hit it to dismpunt your foe.
The on-foot phase is a bit harder but nothing that should cause you too much difficulty. The boss will block all your attacks and counter so you need to take advantage of this.
The main way is to trick him into doing an attack like the leaping sword slash by slashing at him then quickly dodging away so he misses. Once he has missed dash into him and unleash a small combo.
Dodge the blue fireballs he throws and keep countering his counters to kill him and get your horse back.