Challenging Pluto is different in the PS1 version. You'll first need the Emerald Pact Ring that you find in Shadow's cavern (a dungeon replaced with the Dwarven Ruins extension in the GBA version), which requires the Red Lantern, which means you had to have explored Moria fully at least once. Then you have to go all the way back down Moria again, to the area before Wyvern. Walk down into the Daemonium area, and past this hole to initiate the battle.
This is an example of one of those RPG battles that you're supposed to save those one-time use items through the whole game for. I used up almost all of my Chronoglasses, Mahjong Tablets, and a few Elixirs in this battle.
In the PlayStation version, Pluto is very cheap. Unlike the GBA version, you can't just spam Demon Fang on him until he dies. To begin with, he has you pincered with his pet dog, Cerberus, right at the start. While Cerberus is susceptible to the Time Stop effect, Pluto isn't, but thankfully Pluto can be peeped by Piko Piko Hammer. There's also the problem of Pluto surrounding himself with his flames, which means you can never really melee him. Pluto's most dangerous attacks would have to be his flames (which can be guarded, but your AI characters definitely aren't going to be able to guard effectively), and the hands of darkness that periodically rise out of the ground to sodomize your party (around 2,000 a hit, and they hit for some godawful amount of times). I had to equip Black Onyxes on my other three characters so their HP would be high enough to withstand some of these attacks.
The main strategy I used here was, have Arche and Mint freeze time to stop Cerberus, while Cless and Chester focus on Pluto. Mint alternates between healing, peeping Pluto, and freezing time, while Arche uses Big Bang. This worked pretty well up until the end, when I almost died, but at least that made the battle even more exciting.
This is pretty much the end of my Tales of Phantasia boss series. Thank you all for watching!
Cless (Alex) Level 84
-Excalibur
-Golden Armor
-Blue Line Shield
-Golden Helm
-Hyper Gauntlet
-Technical Ring
-Fairy Ring
L2: Chester's Gouten
R2: Arche's Big Bang
Neutral: Jigenzan
Up: Shugohoujin
Down: Jikuusouhazan
Left/Right: Jikuusouhazan
Arche (Dawn) Level 79
-Star Broom
-Witch Dress
-Ring Shield
-Magical Ribbon
-Mother's Gloves
-Black Onyx
-Mystic Symbol
Chester (Joe) Level 78
-Elven Bow (Upgraded)
-Mumbane
-Ring Shield
-Star Beret
-Star Glove
-Fairy Ring
-Black Onyx
Mint (Heather) Level 79
-Blue Crystal Rod
-Star Cloak
-Ring Shield
-Star Beret
-Pretty Mittens
-Black Onyx
-Mystic Symbol
Tags: a Cless Mint Chester Arche テイルズオブファンタジア ボス プルート ケルベロス マニア クレス ミント チェスター アーチェ