EBF5 Neon Valhalla ACE (all challenges epic mode)
https://www.youtube.com/playlist?list=PLzNFGNUJVAhembOte-XM-vds-8IJ4TU-a
Neon Valhalla took 17 attempts. What a complete nightmare of a boss, I had to change my strategy so many times for this to even work at all.
Initially I tried a more refined version of my first playthrough's strategy, with more debuffs and status effect, such as curse, weaken and stuns in an attempt to counter everything, however after a lot of testing, I'm convinced trying to slowplay the fight is impossible, at least with the equipment you're given at this point in the game. There's simply no way to keep up with damage while surviving his attacks, and all of them basically oneshot the entire party every time, on top of the nukes having ludicrous hp and all oneshot due to the weather debuffing your defense all the time. I also tried changing the weather to keep my buffs, but it turns out the harpoons will pretty much always reverse your buffs, so that didn't work either.
At this point I had basically given up and was moving towards Laurelin, but as I got there I decided to try it again with a zerg strategy, this was surprisingly effective, however I had no idea how close I actually was due to hp bars being hidden, except for looking at the tank itself breaking down. After refining the strategy many many times, over 10 times easily, it eventually worked.
There was still a lot of rng involved. For example, Matt was the only one surviving the initial charge, I couldn't really swap to tank gear due to the intense damage requirement and I noticed Anna was only getting overkilled by about 5-10%, so I went and bought permanent stat ups to get her defense up and then relying on NoLegs to dodge the first charge. After that I had to just survive until the first respawn which turned out to be horribly RNG reliant, as most of his attacks will always kill one member.
After many tries of failing due to RNG, I tried invisibility, which is fantastic, however I only had 3 summons so I decided to use 1 before the first respawn, and the other 2 after. The fight ended up being shorter than I expected, so I could've actually used 2 mirrors before the respawn, which would've reduced the RNG by a lot. Shoutout to the stumpy gloop random summon which gave morale and saved everyone from dying.
ACE means enabling every single option in the challenge menu and also playing on epic. This awards stars on existing medals. Several Custom Game options were also included in this.
Full list of challenges included
Epic Mode - 200% foe stats, enemies have new attack patterns
Foe Remix - Different preset foes appear in each battle.
Weather Remix - Different preset weather appears in each area.
Equip Remix - All weapons and armor have a completely new set of stats.
Scaling Foes - Foe levels are always proportionate to yours.
More Foe Resistance - Foes have more resistance to elements and status effects.
Less Player Resistance - Equipment gives roughly 40% less elemental resistance.
Counter-Attacking Foes - Most foes have a chance of counter-attacking when hit.
More Foe Evade - Foes have 10% more evade
More Foe HP - Foes have 20% more HP.
More Foe Attack - Foes have 30% more attack and magic attack.
Foes Act First - After the first wave, foes will attack immediately.
Status Antibody - Foes gain a little bit of resistance to a status effect each time they are inflicted with it.
Even Rewards - Dead players also gain EXP and AP after each battle.
Combo Cap - Damage multiplier is capped at 6x of normal damage.
No Grinding - Foes do not respawn, backup foes do not give EXP or AP.
No Revive Turn - Players revived in battle cannot take their turn immediately. Does not affect Auto-Revive
No Rare Food - Rare food items are banned in battle.
Hide Foe HP - Foe HP bars are hidden in battle.
Turn Time Limit - You have 30 seconds to take your entire turn, excluding animations.