The Master of Exchange (in-game name Vaihdosmestari) is one of the many Master spellcasters. It takes the appearance of a single-eyed blue humanoid and is dressed in a white robe.
The Master of Exchange specializes in Swapper magic, casting homing bolts that deal damage but causes the target and itself to immediately exchange positions. More importantly, this effect also triggers when the Master is damaged by another entity. This can cause the player to be hurt by projectiles that can deal self damage, such as Summon Disc Projectile or any spell with the Piercing Shot spell modifier.
- As with all Masters, exercise caution and focus on avoiding the projectiles. This is easily done by constantly moving perpendicular to the enemy's aiming trajectory (which usually means levitating up or falling down) and staying at a medium distance.
- Slower, hard-hitting spells are recommended to reduce the amount of swapping performed. The Vaihdosmestari has relatively low health, so it should be easier to kill it in one hit, which will prevent the swapping effect from happening.
- If the player does not have such a spell, be sure to fight this enemy in isolation. Its slow speed and unaggressive behavior should make it easy to pick where you fight.
- Accidental kills are another option, as they won't trigger the swapping effect.
- Be careful when using spells that linger or home in on enemies, such as the common late-game Homing + Drilling Shot + projectile combination, as this may cause the player to swap unexpectedly some distance away; possibly into the middle of a crowd of enemies.