Kyurem-b is definitely one of the most threatening mons in the tier and imo it is simply broken. Base 170/120 attacking stats with solid coverage, as well as amazing 125/100/90 bulk to tank most hits well. Why this thing was even allowed to be unbanned from Ubers in the first place is beyond me. The fact that it's BL instead of OU currently just shows you how underrated it really is, which baffles me. With Rotom-W being #1 in OU, its so easy for Kube to get a sub and just start wrecking stuff. but anyways, heres a bunch of sets I've used to tremendous success.
physically based sub attacker
kyurem-b
Leftovers
adamant nature
56 HP/216 attack/236 speed
- sub
- dragon claw
- fusion bolt
- ice beam
set up a sub, which shouldn't be too difficult, and just start wrecking stuff. it beats blissey and chansey which special sets struggle with. dragon claw 2hkoes conkeldurr after SR so thats not an issue. even with a hindering nature, ice beam is enough to 2hko physically defensive mega venusaur. aegislash does fairly well against this, altho you can play around with king's shield and use sub during that turn and try to fusion bolt it when its in blade forme. fusion bolt also does solid damage to mega mawile, assuming no intimidate drop, almost 2hkoing it. Heatran is a problem tho.
specially based sub attacker
kyurem b
Leftovers
mild/modest nature
56 Hp/216 spatk/236 speed
- sub
- ice beam
- earth power
- focus blast/fusion bolt
same set in the first post, but focus blast definitely deserves a mention. even tho its accuracy sucks, it koes bisharp right off the bat, its your best option vs ttar and ferro, among other things. OH AND IT KOES MEGA LUCARIO
Life orb mixed attacker
kyurem-b
Life orb
naughty nature
216attack/100 spatk/192 speed
- fusion bolt
- ice beam
- earth power
- outrage/dragon claw
this is a true terror. LO outrage destroys conkeldurr and blissey, and dragon claw is enough to 2hko them as well. fusion bolt does some pretty awesome stuff like KOing manaphy right off the bat. the combination of Fusion bolt + earth power also KOes many of Kube's common switch ins, such as heatran, aegi, mega mawile, etc. everything else is pretty self explanatory
choiced
kyurem-b @ choice band
adamant
252 attack/4 spdef/252 speed
- outrage
- fusion bolt
- ice beam
- dragon claw
this thing is an absurd wallbreaker and while its not meant to sweep, its used to blast holes 1 by 1 on your opponent's team. CB outrage flat out ohkoes rotom-w, chansey, tyranitar, and a whole plethora of other mons. CB fusion bolt has enough power to 2hko heatran! it also nearly koes genesect and mega luke if they switch in. if your opponent doesnt have a fairy, its very easy just to spam outrage because even most steels are 2hkoed if their physical bulk arent insanely high like forrey & skarm. outrage has the firepower to 2hko scizor and jirachi with SR. if your opponent is using a slow team, this can truely wreck them.
Kyurem-b is a pretty awesome mom. Use him wisely and he can be a tremendous asset with its godly stats and amazing coverage. defensively wise, even though its typing isnt the best, it still has the raw bulk to withstand most hits. (its physical bulk is comparable to that of hippodown's & tangrowth's) altho its special bulk is only slightly less, it offers more resistances like grass, electric, water, making it hard to take down sometimes.