Party:
Crono lv. 1
Marle lv. 4
Robo lv. 16
Recorded and uploaded this video for fans of my Chrono Trigger low level playthrough.
PLEASE READ THIS FIRST, EITHER TO SATISFY YOUR GENUINE CURIOSITY OR TO ENSURE YOU DO NOT POST MORONIC COMMENTS (I as usual hope for the former):
In order to make Spekkio take his final form, your party leader (the one who takes the first spot in your active party and who you move around) needs to be level 99/**. In a low level game, it's obviously impossible without the use of cheats.
However, I wanted to prove myself I am able to defeat Spekkio with a low level party, so I searched for a way out - a way that would break the rules only in order to allow me to fight that boss, without having this violation also make the battle itself easier.
My first idea was to put Magus in the party, have his two allies killed and then grind for experience. I very quickly remembered that, when the Wallet (all experience turns to G) isn't equipped, the reserves outside of the active party still receive experience. While I think there is a way to prevent levelling up the reservesl, for instance, by fighting weaker enemies, I figured I might as well... yes, use a cheat.
This was an aesthetical issue to me, as I've never cared much about cheats and always achieved things the natural way. I used the guide on GameFAQs, but having no knowledge how entering cheats in snes9x works, realised I'd failed. Thanks to dem0nter who literally babysitted me through this process and without whom this otherwise impossible battle would never take place.
ALSO READ: Getting Magus's level to the max was the only thing I cheated. My equipment, characters' stats and inventory was all result of hard work and wasn't affected by cheats. Show that you've failed to read this paragraph by making an ignorant accusation and I'll remove your comment without any thorough consideration.
Now let's move on to the battle.
I decided to use the combination of Marle, Crono and Robo - the same one I had used for the final battle - because of their triple tech Lifeline. In case you don't know, Lifeline sets Auto-Reraise status on all three party members. Crono and Marle need Gold Studs to make it effective (and possible in the first place).
First question is how to defend in this battle. The theme is "elemental protection". Spekkio knows Flare, which is fire-elemental, Luminaire, which deals lightning damage, and Dark Matter, which deals shadow damage. All of them seem to be absorbed, but the one I've seen most often is Luminaire, so I had two characters with lightning protection. I gave Robo protection from fire.
If he casts Luminaire, Robo dies and the battle may go on since there is little risk in losing when two characters remain in Auto-Reraise status (should be applied as fast as possible). If it's Flare, Robo stays alive and revives the following, but since I've never seen Dark Matter used in this battle I just relied on Auto-Reraise.
He may use Salt on your characters which actually heals them (your HP doesn't really matter in this battle, since if you are hit you die, regardless of how much HP you have; the point is that he loses a turn in vain) or he may use the Hallucination attack which reduces HP to 1. I've already explained why this doesn't hurt us at all and is another waste of a turn.
But how do we attack? It's no secret to most CT players that physical attacks and techs miss Spekkio and only magic may damage him. To make matters worse, Spekkio has the best magical defence in the game.
My strategy for offence was to have Crono and Marle use their double tech Ice Sword 2. The magical part ensures it connects and Crono's incredible, for a level 1 character, physical strength complemented by his ultimate weapon Rainbow does very respectable damage. Robo restores the party's MP and sometimes squeezes some Shock spells in for less impressive damage.
I really did get lucky not seeing Dark Matter as much on this attempt.