Justice is a fan-made global mod.

No one said that witches, considering their growth, would be weaker than hydras. They can easily be made the strongest at that level.
For example, do you consider bone dragons the highest tier among the Necropolis creatures just because they are level 7?

Dragons in this position are logical because they rise from the corresponding creatures. The fact that they are weaker than others in the game is irrelevant (we are discussing logic, not the specific power of the creatures). As for the witches, everything is obvious: dragons (the embodiment of Malassa) > witches (the most important of those who worship Malassa) > all others.