Here's a good way in defeating the last boss:

Attack the parts of his body in this order:
1. The Rune
when the rune is gone, DEF and MAG DEF of the boss decreases a little bit.
NOTE: use all might if possible. For example, when a character has a Thunder Rune, use Thunderstorm (1200 damage to 1E) and use a character with Rage and use Final Flame (900 damage to all Es). This will combine the two runes and create an attack called Armageddon (2000 damage to all Es). Make sure your'e characters' levels are above 62 so that it will deal intense damage.

2. The Right Leg
the right leg is an irritating part because if you don't attack it at once when you've defeated the Rune, it will resurrect it. NOTE: the right leg is weak against Thunder element but strong against Earth.

3. Left Head
The left head is powerful even without the Rune's help. When it uses Crystal Fall. It deals at least 120 damage to your characters.

4. Right Head
His attack is the Fire Sword so make sure your characters have Fire Sealing Rune or Fire Amulet to lessen the damage.

5. Left Leg
even if you don't attack this part the boss is defeated because all it can do is cause status problems.

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NOTE: The reason why the Rune must be killed first because of it's UNITE with the two heads which deal at least 200 damage to the characters. (350 damage at maximum.)

Here's my List of Favorite characters to be used in the FINAL BATTLE:
1. Van (the name I give to the hero)
2. Flik (Uses Thunder Rune)
3. Luc (has intense Magic Stats but low STR and DEF)
4. Viktor (has a UNITE with Flik and is very powerful)
5.Lorelai (another good magic user and for support purposes)
6. Georg (Same as Humphrey but has higher Attack Power)

When you can go to Muse City, just go all North until you enter Muse-Matilda Border. The guards says you can't pass!! But, push the wall like you push those boxes in Mercenary Fortress. Go to Highway Village. Talk to Humprey then recruit him ( join with Futch). If you fight monsters without recruiting them, it's nearly imposibble to win!! After recruiting them, I suggest do not fight at Rakutei Mount because there's a lookalike birdie that can take away one character then will not get EXP. You can simply win againts any enemies in world map with Humprey because of it's Prot is totally high but.. Patient is really really needed here!! OK, Good Luck

Here are locations of Highest Rune(s)...

Rage Rune (Fire):
You can get It in Greenhill, just talk too the Runemaster in School!

Cyclone Rune (Wind):
You can get It in Gregminster, just talk too Sarah in Inn, at 2nd floor!

Flowing Rune (Water):
You can get it in Muse City, just talk too the Guy at the 2nd floor, of Runemaster Shop!

Also you can buy it in Gregminster at Rare Finds! It will always come new stocks soo come too Gregminster more than 1s!

Mother Earth Rune (Earth):

You can get It in Tinto City, just talk too Gustav, after you defeat BloodSucker Neclord! You can buy It in Gregminster, sam as Flowing!

Thunder Rune (Lightning):
You can get it in Rocxeck Castle (or someting), talk to the Blue Knight in the same place where Nanmi dies, just a littlebit futher!

Also you can get It from White Knights in Regural battles...but thats very hard!