By the rules, if the entire party is rolling for stealth, only half of them are required to succeed. It's called a group check.

If your fighter was the only one with a bad roll, and your table doesn't use crit fail/crit success on skill checks (which is a homebrew rule, albeit fairly popular), then the result is probably legal.

One thing the other comments aren't mentioning that is relevant: this wasn't free. A second-level spell slot was expended by someone to make this happen, and since this is your first big quest, it's likely that it was a significant resource investment because you're a low level.

That's just Pass without trace for you. That spell is so poorly balanced, it's effectively an auto success on group stealth checks. Just a few things to note here when it comes to RAW:

• There are no crit fails on skill checks
• For a group stealth check it doesn't matter if one party member fails it. It's still a success.

Nat 1s aren't an automatic failure on a skill check in 5e. Your DM played it correctly. Don't try to attribute their actions to going easy on you. They played it by the book.

Seems fine to me. RAW disadvantage gives you -5 to a passive check, so a sleeping creature which normally has 10 passive perception would have an effective 5 instead. With the help of one of the strongest stealth spells in the game you rolled 12, beating their perception easily.

A natural 1 isn't an auto-fail unless it's an attack roll, so unless there were other alarms or noisemaking devices you cleared the encounter. You don't have to fight everything of you don't need to, if you're using xp levelling you'll generally still get full xp for clearing an encounter without combat.

I'm gonna give the DM the benefit of the doubt here, if they didn't want it to be possible, why have the boss be sleeping at all? You didn't get a pass, you fell right into their (metaphorical) trap. Enjoy your false sense of security... for now.

Does your game honour Nat 1 and 20 rolls? If you don't count them as insta fail then I think it's ok.

How do you know the BBEG had a pp of 10?

Did you ask your DM in private about it, told them how you felt let down?

And there are DMs who are pro-fail. I was trying to throw a child over a pit in the cellar floor, rolled something small (6 maybe?), kid fell in the 10 foot hole and insta died. 🤷

Thank you everyone for your thoughts.

I was caught up in the homebrew rule of auto fail nat1s that is NOT in the PHB.

Rules as written we earned that easy win by taking advantage of the bosses low perception and spending a spell slot on pass without a trace.

The way they play in Critical Role is not by the book.