Shin Megami Tensei: Nocturne
Depending on how far you traverse the Kalpas of the Amala Labyrinth early in the game, the White Rider can potentially be the 4th Fiend you face in a battle for the possesion of the Candelabra and Lucifer's favor. The White Rider will appear to the Demi-fiend when they've reached the 2nd Kalpa of the Amala Labyrinth. After threatening the Demi-fiend, he'll start showing up at every major save terminal when you've passed through the Ikebukuro Tunnels and challenge you to a boss battle. This will put the player at a disadvantage in regards to reaching any nearby terminals or Cathedral of Shadows unless you defeat him. It is not impossible to avoid him though it requires a bit of backtracking to the hospital.
Boss Battle Strategy
Unlike Matador and Daisoujou, White Rider will summon two minions to help him in battle. In his case, he'll summon two Virtue's to both heal and buff himself. The best way to counteract this is to evolve a Dis into a Valkyrie with the skill "Stone Gaze". The Virtue's are weak to ailments, so casting Stone Gaze on them should be easy with little chance to miss. Stone Gazing the two minions will force White Rider to waste 2 turns, if you combine this with casting -kaja buffs on your own team he'll waste a turn de-buffing your buffs. Doing this, should make it easy for you to kill him with simple melee attacks while his missions have been reduced to hood ornaments.