The Spire

The Spire Multi-Player Event will be unlock at level 46. Spire also known as the best experience for player and it give us awesome reward too. There are 24 Bosses each will give you boss you kill will get 300,000 Experiences (Experience scroll and Card Set Bonus also boost your experience) and 1 card chest . Here is the boss of each stage in Spire Event.

The Additional Skill
Guardian Shield: Reduce damage taken 90% for 3 turns (120 Seconds CD) Starting 3
Paen of Life: Heal for 50% of your max HP (60 Seconds CD) Starting 3
Vulcan Wraith: Increase damage dealt by 200% for 3 turns (60 Seconds CD) Starting 3
Sacred Nirvana: Revive yourself or you fallen party member (120 Seconds CD) Starting 1

Sometimes a Treasure Thief (a golden goblin) will appear with boss, if the thief defeated it bestow the party with the additional charge of random Spire specific skill.

I only print screen from stage 10, because the lowest stage take it because loading and we only hit once boss die :)