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.

Easy

 * Level: 130
 * HP: 2,100,000,000
 * 5,000,000 EXP, 500 ambition
 * 20 death count, 1% exp loss per death

Normal

 * Level: 170
 * HP: 12,600,000,000
 * 5,000,000 EXP, 500 ambition
 * 20 death count, 1% exp loss per death

Skills

 * Screen Crack which deals 999,999 damage and has a large amount of range
 * Summons Netherworld Monks, which can heal him

Rewards

 * Dominator Pendant recipe
 * Arkarium ring recipes (High Lord, Oracle, Berserker, and Guardian)
 * Mechanator pendant (Easy mode only, lower stats)
 * Occult Cube (not in GMS)
 * Rebirth Flame (not in GMS)
 * Cube Fragments (GMS only)
 * Master Craftsman's Cubes (GMS only)
 * Crusader Coins
 * Ability Circulator
 * Medals of Honor
 * Potions
 * Fragment of Distorted Time (used to upgrade the Dominator Pendant)