Among the first of Jester's enemies, if the Radiance Church were considered to be the first, then the church of Red Sun was not too far off.
To them, the whole existence of Jester was stained by their belief, a being of death that refuses to accept the sun while playing with the living.
It was blasphemy in their eyes and in the past, they have treated Kassandra a bit rudely when the word got out of Jester and her relations with him.
A past that Kassandra treated fondly as she grew up. The hardships molded her into what she was now, it forced her to make her own decisions and not be led by either the church or the Jester.
And she knew, that to fulfill her dream and exact her revenge, she had to request the help of these people that once shunned her.
Of course, they have done the same after they came to believe that Jester was dead, but to prove them wrong, she had followed some clues and reached Durum, before becoming a tower master there.