Embodiment of Claidheamh - Ressa

The spirit of Claidheamh, one of the 5 legendary swords. When defeated, Claidheamh will respawn at it's original spot, and you are free to pull it out. As you do say, you will hear Ressa's voice in your head telling you that you are worthy to wield her, and she will guard you till the end.

Appearance
Takes form as a young woman with red hair and dressed in knight armor. Wields a claymore.

Abilities

 * Claymore Swing: Swings her claymore in a circle, dealing 6 damage to entities within 2 blocks radius
 * Holy Platemail: Immune to arrows
 * Flame Slash: Light her claymore on fire, then slashes at the player's direction, lighting the blocks on fire in a straight line for up to 8 blocks
 * Flame Ring: Claymore Swing fire version. Sets hit entities on fire and also launches fireballs randomly
 * Side Eviscerate: Hits heavily by doing a side slash. Damage can be halved by blocking with a sword. Takes 5 uses off the durability of the weapon you used to block. If hit, deals half of maximum health as damage and takes 10 uses off the durability of worn armor
 * Heavy Execution: Dashes at the player and bring her claymore down onto his head, resulting either 10 damage or an insta-kill

Strategy
Before you start, refer to the following checklist. You're gonna need all these items to fight her. Health Potions to survive her heavy blows, Fire Resistance Potions to survive fire attacks. Potions of Speed to dodge her attacks. Ender Pearls are used to avoid Execution. Throw them to the other side of the room when she starts to dash to avoid certain death. Weapons will break very soon if you block Side Eviscerate instead of dodging, bringing extras will help.
 * A lot of Health Potions
 * At least 3 Fire Resistance Potions
 * Some Potions of Speed
 * Full set enchanted diamond armor
 * Ender Pearls
 * 3 strong weapons that you're willing to lose