Eikthyrnir

Eikthyrnir is a original creature created for the Seven Deadly Sins Grand Cross Game.

Appearance
Much like Hraesvelgr the boss appearance varies on floor to Floor. The normal one resembles a deer like creature with some blue and green colors. In even number phases it horns have orb in between them representing Speed, Strengh or HP Attribute.

Abilities
It was said by Thonar and Grimmir that the water drops from it's horns create rivers of life. and said to be responsible for all life in Midgard of Yggdrasil.

Feriece Rush - I uses it's horns to attack it's foes

Hazy Rush - It speeds and rushes around it's foe to do damage

Splash Shower - It creates sphere water projectiles to attack it's foes

Water Loop - It shoots a single sphere water projectile at it's foes with it;s horns

Icy Pond - it summons in ice ls similar to Ice Fang or Skadi's ice magic to attack it's foes.

Life Explosion - It uses it's life creation powers to unleash a devasating attack

Refresh - It eats grass to get stronger

Bubble Bomb - It summons in bubbles that weaken it's foes

Defense Horn - It uses a countermove that negates damage and will deal a devasating blow when attacked unless the enemy is protected by a barrier

Life Force - It summons in vines similar to Gloxinia's Thornbush to attack it's foes

Frosty Raid - It unleashes a single attack in a single foe by trapping it's foes in a bubble, freeze it and then make it explode.

History
According to Thonar it was resposible for giving all life in Midgard of Yggdrasil and eats Branches of the World Tree on Valhalla,

Seven Deadly Sins: Grand Cross
When trying to spring life back into Midgurd the Seven Deadly Sins, Hawk, Thonar and Grimmir arrive where Eikthyrnir and attempts to bring life back by driving it off back to where it come from.

Trivia

 * Much like Hraesvelgr the game labels it a member of the Fairy Race despite having no connections to them