How Viable is Demon Slayer at Bossing?

They are, for the most part, good bossers.

The amount of status resistance they have is ridiculous.
Binding is very useful in any boss that casts damage reflect as well.

For 1/1's, just use nlc pots or get a pet/perma hp pouch next time they're in the cash shop.

I don't really know a whole lot more about them, since mine is only 120 and I don't play it.

Thanks for the input. A pet is probably a good idea since I'm not the best at watching my HP. Good to know they can do well against DR as well, that is the most annoying status effect in the game.

EDIT: @RedRaven16: Great that they get achiles! I'm used to squishy ranged classes so it is nice that this class has a few defensive skills. I'm also glad about skills not working without enough HP, never really tested this because was afraid to actually die xD.

Sounds like this class is probably better at survival than my MM.