Linda’s Knight in Shining Armor?

Jaime's looks started changing right after he crushed the bottle of Polyjuice potion.

His golden hair turned light brown and his eyes turned black. His ears were elongated, indicating his original lineage. His facial structure and the color of his skin changed as well.

When the revert to his original appearance was complete, Jaime's mana signature was completely changed. Instead of having a scholarly vibe around him, this man exuded the presence of a warrior.

The elven masks were not the only tools of infiltration the kingdom of Layos had employed. The elves had used their superior skills of the potioneering arts to concoct Polyjuice potions for their deep assets inside the enemy kingdom.

With Polyjuice potions, rankers could assume the identity of others. To make the potion, they needed victims' bodies whose identities would be used by the users.