"Finally, I will kill you myself!" Elder Bronx shouted as he released his seal which made him significantly stronger than before.
The Daemos' power is sealed behind the dimensional barrier as this is the price they pay for being linked to the stability of time and space in the universe. This also sealed the deal for the new demons as they will have a hundred times more difficulty in reaching Noblesse status despite their power. This is the reason why the Three Daemos Elders are still in the Arch Demon persona despite their real abilities equating to that of a Noblesse.
This is also the secret of only the powerful beings in the world to never poke the demons to the point that they release the seal. Only demons of Arch Demon persona level can release the seal as long as they have already gotten the qualification of becoming a Noblesse. They can also only use it in areas where the power of the dimensional barrier is weak which is why they cannot easily do it whenever they can.