wht is the most powerful beyblade in the films and series???

is it black dranzer or diablo nemesis, or something else entirely???
I don't know if Beyblades from different series' are compatible in this sense. Every series has it's own power scales, so I don't think they can really be defined on each overs correctly. But, other people have different opinions, so someone else might be able to help you.
For me its L-drago destructor...since it has steal spin capability
It pretty hard to say for all series as there is no real way to compare but as for each series most approite answer will be:-
MFB:- Pegasis Bahamadia SP230R2F
BSB:- Zeus or Dragoon MF (no real way to compare those 2 but I think Dragoon MF as Black Dranzer was defeated by 4 scarced bit beast while Dragoon MF had power of 5 + Wolborg).
Burst:- Unknown or Legend Sprigen/Strike God Vakyrie 6S GRb
This contains spoilers so read at your own risk.

Bakuten Shoot Beyblade
Considering Black Dranzer was beaten by Draciel F, with a bit of help, I wouldn't call it the strongest by far. Zeus is definitely the most powerful in the BSB series, at least since Brooklyn was only using his natural and non improved skills until Tyson and managed to wreck almost everyone easily, and giving Kai with Dranzer MS a hard time.
I guess Dragoon MSUV is really strong too but it wasn't shown enough, but considering it was a much more powerful Dragoon MS and was able to clear the skies and end Zeus' destructive nature.
Metal Fight Beyblade
The most powerful in MFB, and quite possibly of all time in my opinion is Rago and his beyblade Diablo Nemesis. You could say it was mostly the beyblades power doing the work, but it does need Rago to control it, and I'm going by the logic of King and Variares where it was so powerful that only King could control it, I'm assuming it'll be the same for Rago, so Rago probably is skilled too. Diablo Nemesis seems more powerful than every legend blader combined, which are the most powerful bladers in the entire MFB franchise, and we've seen some impressive and powerful non legend bladers too, so that's saying something. I know Ryuga wasn't included in the final fight, but considering Kenta was meant to have his power, it's almost the same as having him. It took Ginga's already naturally strong power + the entire worlds blader spirit + lent power from the legend bladers to beat Nemesis and Ginga only barely won.
Ryuga would definitely be the second strongest as he has massacred almost every opponent he has faced, and has a almost perfect record, and unlike Nile, Ryuga has fought some really impressive opponents like Kyoya, Ginga, Tsubasa, some other legend bladers like King, and beat all of them. He would've probably beaten Chris easily if his battle wasn't interrupted. Ryuga also mastered the legend powers before Ginga and Kyoya did and that was in his early stages of when he had L-Drago Destroy, and after seemed to casually go through rigorous training which can probably be as intense as Kai's, if not more. Ryuga is also probably the only reason why Ginga and Masamune could beat Faust and stop the spiral core machine. I honestly don't believe Faust is stronger than Ryuga tbh.
Beyblade Zero G
Kira with Pegasis Bahamdia SP230R2F is probably the most powerful, as it completely toasted Saramanda Ifraid in a couple of hits the first time. Plus, Bahamdia and Pegasis are probably two of some of the most powerful in Zero G and having them combined will make it even better. With individual beyblades, Sakyo and Kira have both shown destructive powers and rarely lose or struggle too, and Ginga is likely the most powerful as he is a legendary beyblader.
Beyblade Burst
The Burst series hasn't really finished yet, so I can't tell who is the strongest, but for now, three candidates in my opinion are Lui, Red Eye and Free.
Now admittedly, Lui is very powerful but he did have luck on his side for his wins against Shu and Valt, otherwise he would've lost, but he easily beat Kensuke, and Valt in episode 39, and Shu in the past. Lui is said to be the ultimate champion in Japan. I assume that when he gets Nightmare Longinus, he will be crazy strong again.
Free De La Hoya is said to be the number 1 strongest blader in the Burst series so far, and has so far never really faced anyone who he considered challenging, not in the anime at least. Every battle he casually wins without getting worried, he even beat the number 3 blader Josh, and beat bladers like Sisco and Valt easily. He only has drawn once and hasn't lost yet.
Red Eyes is another strong one, I can honestly see him beating Free with his left spin Merge being stronger and that his power combined with his left spin will render Frees god ability useless. So far, he has easily beaten Valt, Daina, Cuza and one shot Gazem without breaking a sweat. He has dual spin and he is really skilled with Merge so he's high versatile too.

These are just my thoughts, I can't really tell who the strongest is for sure, but Rago seems the most powerful to me with his power alone. I am aware I'm missing some key scenes from the manga, such as Valt with his upgraded Valkyrie managing to burst Free and how Ryuga beat Faust in the manga, but for now, I'm just focusing on the anime ones, since my knowledge on the manga isn't that good.

tl:dr - Tough, read my explanations!
thnks for all your detailed responses, only just seen them now as my notifications didn't let me know xD I havent watched beyblade since the original, so needed catching up on all the things i've missed. i wanted too see if there was an equivalent in beyblade too the egyptian god cards in yugioh, in a sense of divine bitbeasts with unlimited power/potential. on another topic, i rlly do like the look of diablo nemesis, but i want too buy the original, official version, is there a hasbro one? i keep seeing tomy takara ones, and rapidity ones, of all different colour variations, which one is the real one???

(Oct. 18, 2017  3:42 PM)Eleanor Wrote: For  me its  L-drago destructor...since it has steal spin capability


tht sounds interesting, how does tht work? i've looked at the wiki, but it doesn't explain much in the way of lore regarding the series
Good Ebay sellers are here: https://worldbeyblade.org/Thread-Good-eB...rom?page=6
Here talks about fake Beyblades: https://worldbeyblade.org/Thread-theflig...ng?page=53
Actually Gingka and BigBang Pegasis, it was able to beat the actually "most powerful bey" (nemesis), needed all blader's force, but he is the onlyone can controll it.
(Oct. 18, 2017  7:49 PM)STAR_TREK_1990 Wrote: thnks for all your detailed responses, only just seen them now as my notifications didn't let me know xD I havent watched beyblade since the original, so needed catching up on all the things i've missed. i wanted too see if there was an equivalent in beyblade too the egyptian god cards in yugioh, in a sense of divine bitbeasts with unlimited power/potential. on another topic, i rlly do like the look of diablo nemesis, but i want too buy the original, official version, is there a hasbro one? i keep seeing tomy takara ones, and rapidity ones, of all different colour variations, which one is the real one???
Takara Tomy is normally the real one, the ebay item name normally says Takara Tomy on it. Hasbro had two versions, one which was a yellow and red and blue version, and the other which was in it's normal colour in a dark blue box with a plastic shell. Takara Tomy seems to be the most common one from my experience.

(Oct. 18, 2017  9:29 PM)aggregor941 Wrote: Actually Gingka and BigBang Pegasis,  it was able to beat the actually "most powerful bey" (nemesis), needed all blader's force, but he is the onlyone can controll it.
While it is true Ginga beat Nemesis, Ginga needed a lot of help to do it, he did just barely survive Diablo Nemesis but he had to have shared power. Plus, he's main character in a taking over the world shounen anime, he was going to win by some miracle anyway.
thnks for all your help =) i'm going too buy diablo nemesis, as it sounds pretty op
(Oct. 18, 2017  10:08 PM)STAR_TREK_1990 Wrote: thnks for all your help =) i'm going too buy diablo nemesis, as it sounds pretty op

Well... it's OP in the show, not sure about IRL. I mean as a stock combo, it does have a bit of stamina and can K.O a lot of beyblades pretty well in attack mode. But it's not OP in real life.
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(Oct. 18, 2017  3:42 PM)Eleanor Wrote: For  me its  L-drago destructor...since it has steal spin capability

tht sounds interesting, how does tht work? i've looked at the wiki, but it doesn't explain much in the way of lore regarding the series
[/quote]

Well from what I know...It uses angular momentum as its weapon...and due its small size when it rotates and when it comes in contact with a heavy and big beyblade...it steals its spin...it would be a lot easier of I could tell u using maths...but lets just say it uses laws of Quantum physics...

But its my personal opinion though...but I really really like that bey...and for me all the left spin beys r the best...I dont really know why....but I think left rotation is the best...
L drago RIP best character and my child hood LOL
RIP the bitbeast....not the beyblade...
Ryuga was the GOD of beyblade one thing in my life ill never get back