After being forced to retreat and gather in a formation to defend themselves as the transformed Havi thwarted their plans to kill the emperor in a battle of attrition. Now, the Pope suggested a way to get out of their predicament and evade certain death.
Because as things stood, the 100 kilometers of the battlefield was no different than a pit of fire because of Havi's constant attacks even though his rank was similar to theirs. Forget about him getting weakened over time… it will be all of them who would fall in battle first.
But as soon as the Pope suggested using one of the church's most prized relics that was handed down from one Pope to another… they all agreed despite the repercussions of being unable to rank up for the next hundred years.
Reference arts for all 4 transformations in chapter comments.