Dicey Dungeons

This is the final boss of the game, and is accessible after beating all six bonus rounds (Round 6 for all six characters). This will happen automatically if using the Edit Progress shortcut in Complete all 36 episodes (90G), taking a minute or two. Otherwise, you'd need to play through and complete every episode with every character, taking easily 20 hours.

For this final boss round, throw everything from other characters and rounds out the window. It doesn't matter which character you pick, because your character specific gimmick is gone (Robot's CPU, Witch's spellbook, etc.). You also don't get XP from enemies, you don't level up, there are no upgrades, no increase to max health, no new cards or equipment, etc. Instead, you fight two enemies per floor, and each one you defeat joins your party. This is critical for the final fight against Lady Luck, because most of her attacks are designed to one-shot you. You'll therefore need party members to take the damage for you, because if you die, you have to start the run over. 

Pick whichever character you're comfortable with and prefer. I used the Thief, but any will do. The biggest challenge on the run through the floors leading up to the boss is keeping track of what attacks all of your allies have, so you know when to switch to them. It's best to, while fighting an enemy, scroll up to view their attacks and take a screenshot. Keep them all handy as you progress so you can take advantage of enemy weakness with party members that do various status effects. Or, if you roll specific high numbers, you know which ally to switch to so that you take advantage of a specific dice roll. All in all, it's not bad though. I didn't do this and made it through all fights without anyone even coming close to dying. Prioritize healing your main dice and then use any other apples for allies. Visit shops and upgrades on priority because you get an extra dice from each. 

Two other important things to mention:
 

• On Floor 4 or Floor 5, an enemy called Rat King will hopefully show up, if you're lucky. If so, Lady Luck will be a piece of cake to beat. If not, you'll have to put more work in. If you find Rat King, defeat him and keep him safe at full health for the Lady Luck fight
• On Floor 5 there will be a boss you can fight to recruit. If you already have Rat King and haven't lost any allies, feel free to skip this boss fight, assuming you're able and if the boss isn't in your way. If you don't have Rat King, you will absolutely need the boss for the final fight. 

On to the final fight against Lady Luck. Hopefully you have Relaxed Mode on so she has 150 HP instead of 200. If you got Rat King, this fight will be easy either way. If not, this will take some luck and save scumming. I will first go through Lady Luck's attacks, because they are set every turn and there is no real RNG in this fight (that'll become clear as I explain her attacks). Also be aware that she rolls all 6s every single time.
 

• Turns 1, 2, and 3: she will do a conditional attack where it checks if your current fighter meets the condition. If so, she does 1 damage. If not, she does 18 damage. These conditions vary tremendously, such as whether you're wearing a hat, if you're green, if you're a poison dealer, etc. I believe these conditions are set such that someone in your party meets the criteria. However, the only way to know is to play the fight, see what criteria she uses, then quit to title and restart the fight. Her criteria won't change. This is the only way to avoid an ally dying during each of her first three turns, since most of your allies have 18 HP or less.
• Turn 4 she won't attack. She will create a rule that will harm you if you don't follow it, such as don't change fighters, don't use countdowns, etc. This is basically a free round to attack for you, as long as you pay attention to the rule
• Turn 5 she again won't attack, she'll just use a blessing (such as giving herself shield or armor or something passive) but the rule is still in place
• Turns 6+ she will use an incredible strong countdown attack (which she'll have no problem with since she rolls only 6s) that will likely one-shot whoever you're using unless they are strong against the status attack, have shield/armor, or you've somehow froze and/or locked her dice so she can't finish her countdown

Basically, you want to get in as much damage as possible and deal with the RNG from the first few rounds as good as possible, because in Turns 6+ is when you'll likely start losing an ally each turn.

Thankfully, if you got the Rat King ally, this fight is a piece of cake and RNG doesn't really matter much, because you can follow these exact steps:
 

1. Turn 1 - switch to Rat King and use all of your dice properly to activate as many stacks of poison as you can. Rat King will get hit by the RNG attack and each take 1 damage if you're lucky or 18 damage if you aren't. Either way, Rat King will survive the attack and that's all that matters
2. Turn 2 - starting with Rat King, again use your dice smartly to stack as much poison as you can. When done, before ending your turn, swap in any random NPC ally. They will die
3. Turn 3 - you'll be allowed to start with Rat King since your ally died. Repeat same as above stacking poison and then switch to an ally to sacrifice
4. Turn 4 - you'll again start with Rat King since your ally died, stack all your poison, but no need to switch out since she will just create a rule on her turn
5. Turn 5+ - stack Poison and switch to a sacrificial ally to die

It's really that simple. Spend your turn adding Poison stacks and then switch to an ally that'll die in one hit so you can start with Rat King on your next turn. I comfortably got up to 30+ stacks of Poison before Lady Luck died, and I probably finished by Turn 7 or so, with zero risk of dying.

If you didn't get Rat King, this will be a little trickier because you'll need to actually worry about the dice you get and dealing damage. However, I still recommend a similar approach as above, but instead of using the Rat King to stack poison every round, put in your best damage dealer and then swap in a sacrificial ally. For example, I got Audrey as my Floor 5 boss and brought her with me. Her countdown attack is very good if you can keep proccing it, because not only does it do decent damage but it also severely weakens Lady Luck, making it way easier to survive her onslaught of OP attacks. Unfortunately, this will also come down to knowing the attacks of your party members (so hopefully you still have those screenshots or mental notes from the dungeon progression), so you can swap in the best allies depending on your dice rolls. Worst case, you can quit to title to retry the fight if you are about to die, and you can manage things differently. With Relaxed Mode and 150 HP, it shouldn't be too bad.