Yggdrasil, the World Tree (ABC-BG-004 RR) [Arcana Battle Colosseum]

If damage dealt by a card your opponent controls would reduce your life to 0 or less for the first time this game, it reduces your life to 100 instead. Then you may search your main deck and/or hand for up to one card named "Avatar of the Seven Lands, Alice" and up to one card named "Blade of the Seven Lands, Excalibur X" and put them into your field. Then shuffle your main deck.