I just beat every boss in OT_0 with only the main character!
OMG after 56 hours of gameplay I've managed to complete the entire game with only the MC in my party (Except for parts where certain companions are mandatory).
I've finally just wrapped up the challenge with Amatsukami No Orochi, which was one heck of a puzzle to beat and required a lot of trial and error.
I've included screenshots for the exact build I ended up settling for.
I don't know if this has been done before, I'm sure it had, but I'm still proud of myself and wanted to share!
For the fellow nerds among you who'd like an explanation of why I ended up picking the build I did and what strategy I went for, here it goes:
Class: Cleric
I did most of the game as Warrior, but settled on Cleric for the Orochi fight because of the specific pattern his weakness change has. Since both of the Cleric's weapons are in the same weakness groups as Dark, I only needed one additional skill, Lux Congerere, to be able to target Orochi's weaknesses every turn.
The Thief also has that advantage, but the Cleric's weapons and skills were more useful to this fight overall (Getting access to HP Recovery Up, the Sunshadow Staff & Forbidden Fan all at once, on top of having great single-target offensive skills was too good to pass up).
Equipment:
The Sunshadow Staff increases Light damage by about 25% and the Forbidden Fan makes your attacks hit one more time, both of which were insanely useful.
Since my stats were maxxed out from eating so many nuts, the shield, helmet and robe were chosen not for their stats but for the recovery they give every turn (Which gets amplified by HP Recovery Up)
The Champion's Mark is absolutely necessary to avoid status effects and get a free second life (Which means you can attack with less fear) and the Finisher's Claws, after testing, had the best damage increase overall.
Skills (Battle):
Whatever could hit at least one weak point from each of Orochi's weakness sets. At maximum accuracy, Batter usually hits 4-6 times.
Skills (Support):
Good luck getting enough damage in before the boss insta-kills you without Surpassing Power. Patience is also basically mandatory, as it allows you free turns to deal damage, target weak points and heal.
Helper: Sea-Gazing Graybeard
The only correct choice. He can attack anywhere between 3 and 10 times, nobody else can do this.
Food: Rejuvenating Seafood Sauté
Is affected by HP Recovery Up, I think. The recovery means you can spend your first 15 turns only worrying about damage and nothing else.
Strategy:
First turn, I used Bran's Blade since Orochi always starts with the Sword & Light weakness set, then rotates to Spear & Fan, Staff, Light and then back around. Orochi's first phase has low enough shield that you can afford to do just 1 shield damage, and you need every point of damage you can get.
After that, it's all about ignoring the orb and hitting weakpoints as many times as possible without using our helper yet, since we need him for later. Only use BP on physical skills for maximum damage, and be careful not to break his shield too early, since you'll need as many turns as you can possibly get to take him down. If you have free turns, use a Rejuvenating Jam to refill all your resources, or use Bran's Blade for damage if it's available.
After the first break, you'll need a bit of luck, and you'll need to use your helper once or twice. The best way to use him is to wait for Orochi's weakness set to be Sword & Light, then select Graybeard and use either a Light attack or Bran's Blade. Your attack will make his weaknesses switch to Spear & Fan, which Graybeard can take advantage of. Just pray he attacks more than 3 times.
After the second break, it's a race against the clock. At this point, your food effect will run out, Orochi will have multiple orbs and do tons of damage to you every turn. What worked for me was to ignore his shield during that phase and alternate between using Rejuvenating Jam and Draefendi's Rage along with other helpers until the orbs were gone, then do the same thing with Bran's Blade on Orochi himself.
If you're lucky like me you should be able to finish him on the last second before he uses his insta-wipe skill, or even sooner if you're luckier or better at the game than me.
Anyway, this was quite the adventure, I absolutely adore this game, and thank you if you read this far. <3 Good luck to you if you want to attempt the same challenge, or one-up me, you got this!