For 10 points, name this trickster god of Norse myth.
This god's wife was Sigyn, who bore him a son, Narfi.  This god prevented an ice-giant from finishing a fortress by sleeping with Svaldifari and giving birth to Sleipnir.  He helped retrieve Idun's golden apples and had several children with the female giant Angraboda.  He will be imprisoned until Ragnarok, when he will kill and be killed by Heimdall, and among his children are the Midgard Serpent, Hel, and Fenrir.  His imprisonment was due to causing Hodr to kill Baldur.  For 10 points, name this trickster god of Norse myth.
This god's wife was Sigyn, who bore him a son, Narfi.  This god prevented an ice-giant from finishing a fortress by sleeping with Svaldifari and giving birth to Sleipnir.  
Loki