Infinity Prison

Unlimited Imprisonment is a skill that seals the target in endless time and imaginary space (an alternate dimension), but the target can still be perceived and felt in the real world as long as Target are powerful enough like the True Dragons. You cannot interfere with the skill from within. It does not weaken over time.

It cannot be damaged via Physical Damage.

History
This skill was used by the hero Chloe O'Bell used it to shield herself from Veldora's attack then used it to imprison Veldora three hundred years prior to the current story. The prison was strong enough to trap one of the True Dragons.

However, the prison did not suppress Veldora's demonic aura or his mind because of him being one of the True Dragons. He was also able to communicate with Rimuru through telepathy. The rest of his abilities and movements were sealed. Although in the Anime He can move His head while talking via Telepathy.