If you control an "Aesir" monster: You can negate the effects of all face-up cards your opponent currently controls until the end of this turn (even if this card leaves the field). You can Tribute 1 "Nordic" monster, then target 1 "Aesir" monster in your GY; Special Summon it. You can only use 1 "Nordic Relic Svalinn" effect per turn, and only once that turn.