MapleStory/Arkarium

Arkarium is the final boss of the Silent Crusade/Cross Hunter storyline. He can be found in the Temple of Time, through the Dimensional Schism. Arkarium is one of the Black Mage's commanders, responsible for sealing the Transcendence of Time, Rhinne.
 * There are 3 modes: Easy, Normal, and Crazy, the latter being only available in JMS.

Pre-requisites

 * Completed Silent Crusade fully.
 * Level 130 or higher for both modes.
 * Maximum 1 entry daily regardless of mode.

Overall stats
Both modes have a 30 minute time limit.

Easy

 * Level: 140
 * HP: 2,100,000,000
 * DEF: 60%, resists all elements including Physical
 * 5,000,000 EXP, 500 ambition
 * 5 death count

Normal

 * Level: 170
 * HP: 12,600,000,000
 * DEF: 90%, resists all elements including Physical
 * 50,000,000 EXP, 500 ambition
 * 5 death count

Skills

 * Screen Crack which deals 999,999 damage and has a large amount of range
 * Summons Netherworld Monks, which can heal him and themselves
 * Throws a blue ball at you (40% damage)
 * Blue thunder rain attack
 * Pinpoint target (debuff you so that you take more damage for non HP-based attacks)
 * Petrify (Tap repeatedly left, right arrow key to get out, or else instantly die after 15 seconds)
 * Cancel Weapon damage (Reduce physical damage taken to 1)
 * Cancel magic damage (Reduce magical damage taken to 1)
 * Damage reflect
 * Genesis (Spots that will be hit are marked 3 seconds before dealing 40% damage)
 * Banish (sends player to a void-like room with a weak monster that resembles the player; player can freely use buffs here)
 * Transform a player into a snake
 * Seduce

Rewards

 * Dominator Pendant recipe
 * Dominator Pendant (super low drop rate)
 * Arkarium ring recipes (High Lord, Oracle, Berserker, and Guardian)
 * Mechanator pendant
 * Occult Cube (not in GMS)
 * Rebirth Flame Level 130 (not in GMS)
 * Cube Fragments (GMS only)
 * Master Craftsman's Cubes (GMS only)
 * Crusader Coins
 * Boss Medals of Honor
 * Potions
 * Fragment of Distorted Time (used to upgrade the Dominator Pendant)
 * Arkarium Soul shard (collect 10 for a weapon soul)