The whole plan was a bunch of jumbled up mess made to not just confuse the main characters in it, but also those that will watch them.
The whole world was aware of Wilkis's ascendance. And with this personality and habits being even more well known, it would be weird for those in power to not predict failure due to it.
The amount of randomness and unpredictability that Wilkis brought to the table was huge, made worse by the fact that very few were aware of the path Wilis took and where his speciality lay.
Making many of their plans useless.
They needed someone stronger to handle or hide away from Wilkis. An individual with a specific set of skills that can survive as well as hide away from Wilkis as long as to take Alfin hostage.
And the only person to achieve this was immortal.
He was the only individual that can change his skin and even stand up to Wilkis if the need arises.
And as it was, their predictions came true.
Wilkis was strong.