A sovereign of law's strength is dependent on their concept. It is a fact that the more complex the concept is, the more powerful it will be. But there are exceptions to it. A weaker concept can defeat a stronger concept if it counters it. Even more bizarre is that some creatures can shrug off the effects of any concept attacking them. Complexity does not mean absolute strength. That's why the power range of Sovereigns is too wide. A sovereign that you can't beat can be beaten by a sovereign that you can bully.
Dragons are the creatures that come to mind in a situation like that. They are incredibly resistant to all types of physical, magical, and spiritual damage. Tandrak's concept will work on a dragon but it will be agonizingly slow especially if that dragon has acquired their special divine body. Dragons always trump drakes. Even if that drake has the power of thunder.
