One of the best tools an Oracle has when it comes to subverting evil, is gradually guiding the evil doer on a trajectory of self-destruction.
This must be done passively, taking no direction action. If remediation is possible, it ought to be done. If it is impossible, use the flaws of the tyrant against them. Are they overly arrogant? Inflate their ego farther. Are they ignorant? Praise the falsities they believe. Do they think themselves indestructible? Bow before them, even if they are insignificant.
Then, at long last, watch the slow…gradual decline. At any point, should they seek guidance, remediation, repentance….it should be given freely and without judgement.
Tragically they seldom do. Thus, their own arrogance, ego, and oppression seals their tumultuous fate.
It is critical though to aim them away from the innocent on their journey downward. Are they violent? Do not encourage violence, or support that idea. Are they sexual predators? Do not praise their sexual prowess. Find one of their other flaws. Do not pick one that could hurt others.
Sometimes it takes years, months. But the trajectory will never fail, so long as their evil ways do not change.