How do I beat Bituitus for mission 7?

If you actually submitted helpful information like how far you are in the Crystarium, what paradigms you're using in your attempts, what equipment you're using and things like that, people could help.
Hmmm... starting to see a lot of empty help requests guys, come on! We're better than that...

I assume you wanta simpler solution and not the whole long deal. If you want a long response reply again and I will post it, but I will keep it short for now.

Basically, to make this easiest you will want:
1. Sentinel (he has strong melee attacks)
2. Someone that can cast protect (the sentinel must always have protect up)
3. A double sentinel capable party is useful (damage reduction to help live thru the levibolts)
4. A leader who can summon a non-elemental eidolen.

Ok, he starts using double levibolts when he gets below 200,000 HP or so. He will start with a double, then alternate between a single and a double. Usually a Com/Sen/Med can make it thru the singles just fine, but for the doubles go Sen/Sen/Med if you are having trouble surviving.

When he gets below 115,000 health or so he begins using triple levibolts. You essentially need to survive thru just one of these. After recovering from that just keep on attacking him and heal up.

By the time his second set of three levibolts come up, you want to live thru the first two, then Eidolen Cancel the third. Fang is good for this because Bahamut does great damage and so does ruin when in Com.

When he starts to ready another triple levibolt, go gesalt mode and try to finish him off. You should have no problem doing the damage. If not, you'll have to survive thru a triple levibolt right when the summon ends.

If this is not helpful enough, read the post at the top of this thread, which details my strategy for this on NCU. It may help you out.
www.gamefaqs.com/boards/genmessage.php?board=928790&topic=54073481&page=17

Just saw this because I've been farming for tiara and thought I'd throw something out there. I've been killing this dude for about an hour now and each fight lasts about a minute to a minute and half. I open the fight with Lightning, Snow, and Sazh setup as MED/SEN/SYN to make "Protection"... Let Sazh buff it up while Light keeps everyone alive, then switch to "Cerberus" or COM/COM/COM and spam him with Ruin... It kills him before he can start spamming his lightning attack. If you get low on HP, switch over to "Solidarity" or MED/SEN/COM and use Light to heal up while Snow tanks and Sazh keeps plugging away at him with Ruin. "Solidarity" is incredibly stable in this fight, it just takes awhile to kill him this way.

I realise that this thread is quite old, but since it came up high when I googled it, I assume alot of people have the same question.

I had a little trouble beating this guy, but I had big issues when it came to getting five stars on the fight. Therefor I read up on various strategies on the internet, but none of them worked for me. Eventually I found my own strategy which worked wonders for me.

Team: Lightning, Fang, Vanille.
Paradigms: Med/Sab/sab, Med/Sent/med, Com/Com/Rav

My team consists of Lightning, Fang and Vanille. As you know if you have used Libra on the boss he has halved damage taken from magic attacks, therefor I start off with a Med/Sab/Sab Paradigm.

Your first move depends on luck. If your lucky with the first breath, use Esuna remove the negative buffs of your party. When that is done your sabs should already have stacked about 6 negative buffs on the boss. Switch to Med/sent/med to heal up fast. When your party is on full health, switch to Com/com/Rav and burn the boss down.

If you have to heal again, switch to the med/sent/med paradigm, but usualy it should not be necessary. This tactic beats the boss in about 1:25, granting you 5 stars.

As I did this, I also decided to level Vanille as com, just to get her the Ruin spell, which does the most damage and is very early in her commander crystarium.

Good luck!

My personal setup and strategy:
Leader: Vanille
Party: Vanille/ Sazh/ Snow
States
*Protection (MED/SYN/SEN)
Solidarity (MED/COM/SEN)
Matador (SAB/RAV/SEN)
Diversity (MED/RAV/COM) (redundant)
Ruthless (SAB/RAV/COM)
Target Fire (RAV/RAV/COM)

Boss starts with Miasma. I remove deprotect and deshell on Snow, then remove deshell on the rest, and then start healing. Protection may be switched out for Solidarity as soon as Sazh has Haste, Vigilance and Faith. Poison and Brave may be ignored.
Switch to matador when party life is green. Switch back to solidarity when Levinbolt starts. Continue this cycle. As saboteur, input actions manually.
When the boss is close to stagger, switch or either ruthless or target fire. Aggression should help and perhaps be used over diversity.

NOTES:
-Very importantly, I was extremely under leveled for this battle. I had in fact prided myself on being able to skip all but two encounters on the path here from Chapter 11's start.
-Since damage is intended to be back loaded, playing Sazh as leader may be a good idea with manual input, and malevolence state be used over ruthless. Late faith will lower damage output in the beginning and delay the double levinbolt.
-Each character has flaws in its AI for some critical roles. I played Vanille as leader because her medic AI does not ignore poison and her saboteur AI cuts actions when all viable debuffs are applied. Snow's sentinel AI does not separate itself from the party, and Sazh buffs himself last.

Modifications:
The main one I see it dropping Sazh for Hope. This fixes the one medic issue and provides a stronger defense to offset the complete lack of offense that being low level inherently brings. For this fight in particular, Hope seems to be the hard counter. Veil protects against miasma, Protect helps the sentinel, shell helps defend against levinbolt, and barthunder helps defend against levinbolt. The only thing lost is haste, which is a small price to pay for never ever ever dying ever.