Text (GP+errata): If ~this~ is in your opening hand, you may begin the game with it on the battlefield. ; All nonland permanents are legendary. [Oracle 2009/07/08]
The "legend rule" causes all legendary permanents with the same name as each other to be put into their owner's graveyard. Notably, this card wipes out all token creatures with the same name. [Guildpact FAQ 2005/12/22]
If the game starts with more than one Leyline of Singularity in play, they will each be put into their owners' graveyards right after the upkeep of the first turn starts. If the game started with multiple copies of any other Leylines in play, they'll be put into the graveyard at the same time. [Guildpact FAQ 2005/12/22]
Adding a supertype doesn't overwrite other supertypes. Each nonland permanent will be legendary in addition to its other supertypes. [Guildpact FAQ 2005/12/22]
The timing of Leyline cards at the start of the game is described in Rule 103.Ruling.1. [D'Angelo 2006/01/22]
