Since the mystic Slayers have got an update, and are now officially named as a caste, I made this thread for card ideas of the Mystic Slayers that you all can share. I'll start off.

Beatrice
Race: Human
Gender: Female
Guild: Mercenaries
Class: Marauder
Levels: 3
Spirit: 2
Attack: 7/10
Defense: 2
HP: 15
Rarity: Common
Mystic Slayer
Spirit +2 and Attack +2 against Mages
At the start of the fight, "Beatrice" has -X to magic damage suffered, where X equals how many Mystic Slayers you control (dead or alive)
Turns 1 and 5: The next Spell card played is ignored.
"She's remarkably strong for a girl of her age."

Magic Syphon Armor
Card: Item
Class: Marauder
Rarity: Uncommon
Item Armor
Defense + 2 & Spirit +1 Permanent
Mystic Slayer: Your character has -2 to magic damage suffered.

Rune of Magic Warding
Card Image: a necklace that has runes surrounding it (same as the runes on Mystic Slayer lvl 3).
Guild: None
Race: None
Class: None
Card Description:
Item - Jewel
Unique
Duration: 2 Fights
Spell Immunity for the first spell played by the opposing character.
Mystic Slayer:+X attack until the end of the turn, where X is the damage you should have suffered from the spell.

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Every 5 seconds a prinny is thrown.

Nice one!

It also protects the wearer from spell damage when he is tapped (well, only the first magic damage for that turn).

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Every 5 seconds a prinny is thrown.

Krauser
Race: Human
Gender: Male
Guild: Mercenaries
Class: Marauder
Levels: 2
Spirit: 1
Attack: 8/11
Defense: 2
HP: 16
Rarity: Rare
Mystic Slayer - Champion
Attack +1 and Defense +1 against Guemelites
If your Mystic Slayers play a Marauder card, and it has a restricted bonus, they obtains the bonus, ignoring the restriction.
Turns 2 and 6: the items attached to you cannot be discarded
Flavor text: One of Chantelain's prized pupils.

Judessi
Race: Elfine
Gender: Female
Guild: Mercenaries
Class: Marauder
Levels: 3
Spirit: 1
Attack: 7/10
Defense: 2
HP: 14
Rarity: Uncommon
Mystic Slayer
Spirit +1 and Defense +1 against Mages and Warriors
If a Mystic Slayer suffered damage since "Judessi's" last fight, she deals an additional physical attack equal to her attack min. to her opposing chatacter
Turns 1, 3, and 5: Defense +1

Name: Total Isolation
Race: None
Guild: None
Class: Marauder
Rarity: Uncommon
Action
At the start of the game if all your characters are non mulit-class marauders,the first copy of this card in your deck is added to your hand.Bonuses from out-of-combat characters are ignored and attack +X where is equals to the number of tapped characters
Chain
Mystic Slayer: All out-of-combat characters are tapped. And cards played by your opponent that targets his deck, hand and discard pile are ignored if the opposing character is a mage or priest.

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Every 5 seconds a prinny is thrown.

Great one!

Here's a priest hate card
Name: Levitating Italian Pasta Dish Fiend
Race: None
Class: None
Guild: None
Pet
Attack and Defense +1 until the end of the turn for each Theurgy played by the opposing character.
Mystic Slayer - Your marauders heal 2 points at the end of the turn if your opponent plays a Theurgy. Theurgies played by the opposing character is remove from the game instead of going to the discard pile.

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Every 5 seconds a prinny is thrown.

Ha! Nice name!