Why is Beryl wearing the muzzle again??

Because he is a beast or smth, in one chapter from before we can see that he lost control and turned into beast mode or whatever it is and apparently that octopus doctor forgot his name made beryl or turned him into human because he is actually a monster, and he is first successful monster turned into human although he lost control not long ago

Now I remember. Thank you

No problem (ㆁωㆁ)