Baron Nashor

Baron Nashor, the most powerful minion, is supposed to be Roshan homologue(his name being an anagram of Roshan) in League of Legends. He appears after 15 minutes on the Summoner's Rift Field of Justice. He is very difficult to take down without a full team unless in the later stages of the game (average player lvl ~13+) and next to impossible to solo due to his 'Wrath of the Ancients' ability which increases damage dealt by him for each stack on the champion.

Killing the Baron gives the "Exalted with Baron Nashor" buff to all living champions on the team that killed him. This buff gives massively increased attack damage and ability power as well as a bonus in health and mana regeneration.

There was a tournament between the beta testers called Baron Nashor's Cup.

Exalted with Baron Nashor
After Baron Nashor is slain, all living players on the team that killed him gain a buff that lasts 8 minutes with the following attributes:
 * 40 Ability Power
 * 40 Damage
 * 3% increase in Health Regeneration
 * 1% increase in Mana Regeneration

Each player on the team is also granted the following: Unlike other minion buffs, this minion buff is not transferred when a champion that has it is slain by an enemy champion.
 * 900 Experience Points
 * 250 Gold