How did I finish another party right after making a different party? I reused two members and were training the other three while I was making the second party. Yep.
Anyways, finally defeated the non-weakened Warped Savior, thus truly completing EO4, one can say. Just in time for a new game I got. I'll talk about that later.
Medic + Landsknecht sub
Healer during the battle with the bug.
When the party is prepared to attack, she uses Star Drop from Vanguard lowering the enemy's defense.
Landsknecht + Bushi sub
Bushi's Blood Surge for pure power. Charge -> Bushi's area attack (that one that uses HP) destroys all of the tentacles and claws in one turn.
Dancer + Bushi sub
Bushi's Blood Surge for more power.
Dancer is really helpful in building up the Burst meter in one turn (required to defend against Ragnorak). Chase and Rush dances to help fuel and synchronize with Link attacks.
Sniper + Bushi sub
Bushi's Blood Surge for more power. Reused.
Squall Volley not only deals great damage, but it can cause Link to activate for each hit Squall Volley does. (Up to a limit, of course)
Imperial + Bushi
Bushi's Blood Surge for more power. Never can go wrong with Imperials when you are looking for brute power.
The non-weakened Warped Savior is a whole different battle from the weakened one.
Not only does it have twice the HP, but it is no longer weak to every element. So it actually has 4 times the vitality of the weakened version!
On top of that, all 4 arms attack at the same time, instead of rotation. On top of that, their attack power is higher. This means you receive more than twice the damage as you would if Savior was weakened.
Also, Savior's attacks when his eyes open become random. That said, there are no elemental guards in this game, so it isn't that different. As the elemental attacks also increase in power, without any resistance up effects, your party can be decimated in one hit. (It already hurt a lot when Savior was weakened...)
Finally, Savior uses two more moves if he is not weakened. One that lowers your Burst gauge by 1 level and the other attack, Ragnorak, that 100% INSTANT DEATHs your entire party. This attack does not miss, cannot be stopped by binds, and ignores any resistance you have. The most certain way to stop it is to use Geo Impact on the turn the eye opens, but the other skill lowers your Burst gauge. On top of that, you only have one turn to build it back up to 5 before Savior uses Ragnorak.
If you can't stop this move, there is no way you will win.
So I went for the "Defeat Savior before he defeats you" route. As you can see, every attacker has a Bushi sub and Medic's Star Drop complements this.
Anyways, it takes 13 turns to defeat Savior. Heck, the party cannot survive past the 13th turn.
For the bug, the party spends 8 turns buffing up and bringing Imperial into Ignition mode. After defeating the bug on the 8th turn, Landsknecht immediately destroys all of the tentacles and claws.
After the Burst counter is reduced, the right moves and buffs will be able to restore it back to 5, in order to use Geo Impact to stop Ragnorak from coming. This will be the 11th turn. On this turn and the following two turns, the party will enter Link mode. Star Drop -> Link
Rush + Chase dance + Squall Volley + Drives.
On the 12th turn, they will indeed be hit by Savior's elemental attack. However, all except the Medic will survive thanks to Bushi's passive skill. (Imperial will move after the attack, thus killing herself from Blood Surge)
The 13th turn has a Link attack by the remaining three characters and this took down Savior.
There are even faster ways to defeat Savior, but anyways, you have to use a team that can deal out big damage quickly. That, or you have to find a way to survive Savior's attacks or skip them. It is possible to survive all of Savior's attacks with a defensive team, but that will take a long time. There is also a way to get Savior to skip his elemental attacks (without any of his arms, his Void attack is survivable normally).
But the amount of time it takes to build the team doesn't change, so I chose an offensive Link team, which can deal a lot of damage in a very short time.