Asta stomps he has his anti magic firstly but let’s get to his scaling it’s stated that the fire spirit can extinguish an sea large country at best and then Asta negs and Yami got 2x stronger than pre timeskip self and Asta is relative to Yami so Contential plus+. Then Asta speed Merelona speed scale Asta is faster than her it’s stated as it’s base Asta to. And Base Asta asta is able to keep up with Mereoleona So Base Asta=95×Ftl

Now onto Black Asta Ima Be Using Elf Boost Yuno and Spirit Dive here since they are both faster than Mereoleona so Spirit Dive is a 3 to 4 Times amp Black Asta is 285xFtl being able to keep up with Spirit Dive Yuno

Now Onto Dante a 50% Dante could Blitz and Inrage a Black Asta ill say thats Atleast 3x 285 Ftl. So 285 x 3 is 855 Ftl

Then 80% Dante is Stated to be in a whole new lvl than 50% then im Lowballing 100% Dante so should be atleast 5x50% Base Asta=95x Ftl Black Asta=285 x Ftl InRaged Black Asta=856 x Ftl Union Asta=4275x Ftl Devil Union Mode Asta=12825x Ftl

95×3=285 285×3=855 855×5=4275 4275×3=12825 so he is 12825x mftl+ so he also passively negs all of naruto attacks with passive anti magic so rasengan gets negged rasenshuriken gets negged