Vanguard

Just because the highest level Tribulation of the True Martial World until now had been an Eighth Revolution Elemental Rage of the Heavens Tribulation didn't mean that this was the highest form of Tribulation there was… 

In fact, Ryu had already faced higher. In the Fiend World, he had faced off against his own Elemental Tribulation before, fighting against tides of fire, winds, and others. 

But the truth of the matter was that the Elemental Tribulations that those of the True Martial World knew of weren't even the strongest in existence. 

In stronger worlds, these Elemental Tribulations were known as Lower Elemental Tribulations, Tribulations that only encompassed Fire, Water, Earth, and Wind. There were also Incomplete Elemental Tribulations beneath that that could only have one or a few of the four, but not all of them.