The Ultimate Power. The user of this ability contains a smaller, imperfect echo of the entire universe, enabling them to search out paths through probability to any desired future. If this sounds like a ridiculously powerful ability, you're right—game balance goes right out the window with this one. Extremely rare among life forms, it is the sekai no ougi or "hidden technique of the world".
Nothing can oppose the Ultimate Power except the Ultimate Power. Any less-than-ultimate Power will simply be "comprehended" by the Ultimate and disrupted in some inconceivable fashion, or even absorbed into the Ultimates' own power base. For this reason the Ultimate Power is sometimes called the "master technique of techniques" or the "trump card that trumps all other trumps". The more powerful Ultimates can stretch their "comprehension" across galactic distances and aeons of time, and even perceive the bizarre laws of the hidden "world beneath the world".
Ultimates have been killed by immense natural catastrophes, or by extremely swift surprise attacks that give them no chance to use their power. But all such victories are ultimately a matter of luck—it does not confront the Ultimates on their own probability-bending level, and if they survive they will begin to bend Time to avoid future attacks.